Aromatic isothiocyanates

ABSTRACT

The present invention relates to aromatic isothiocyanates of formula U 
                         
as defined in claim  1 , to liquid-crystalline media comprising one or more compounds of formula U and to high-frequency components comprising these media, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, tunable filters, tunable metamaterial structures, and electronic beam steering antennas, e.g. phased array antennas.

The present invention relates to aromatic isothiocyanates,liquid-crystalline media comprising same, and to high-frequencycomponents comprising these media, especially microwave components forhigh-frequency devices, such as devices for shifting the phase ofmicrowaves, tunable filters, tunable metamaterial structures, andelectronic beam steering antennas (e.g. phased array antennas), and todevices comprising said components.

Liquid-crystalline media have a been used for many years inelectro-optical displays (liquid crystal displays: LCDs) in order todisplay information. More recently, however, liquid-crystalline mediahave also been proposed for use in components for microwave technology,such as, for example, in DE 10 2004 029 429.1 A and in JP 2005-120208(A).

A. Gaebler, F. Goelden, S. Müller, A. Penirschke and R. Jakoby “DirectSimulation of Material Permittivites using an Eigen-SusceptibilityFormulation of the Vector Variational Approach”, 12MTC2009—International Instrumentation and Measurement TechnologyConference, Singapore, 2009 (IEEE), pp. 463-467, describe thecorresponding properties of the known liquid-crystal mixture E7 (MerckKGaA, Germany).

DE 10 2004 029 429 A describes the use of liquid-crystal media inmicrowave technology, inter alia in phase shifters. Therein,liquid-crystalline media with respect to their properties in thecorresponding frequency range have been discussed and liquid-crystallinemedia based on mixtures of mostly aromatic nitriles and isothiocyanateshave been shown.

Fluorine atoms are commonly used in mesogenic compounds to introducepolarity. Especially in combination with a terminal NCS group highdielectric anisotropy values can be achieved.

In WO 2014/116238 A1 a perfluorinated biphenylyl isothiocyanate isproposed for the use in a chemical sensing device. Any mesogenicproperties are not discussed.

In EP 2 982 730 A1, mixtures are described that completely consist ofisothiocyanate compounds.

However, compositions available for the use in microwave applicationsare still afflicted with several disadvantages. It is required toimprove these media with respect to their general physical properties,the shelf life and the stability under operation in a device. In view ofthe multitude of different parameters which have to be considered andimproved for the development of liquid crystalline media for microwaveapplication it is desirable to have a broader range of possible mixturecomponents for the development of such liquid-crystalline media.

An object of the present invention is to provide a compound for the usein liquid crystalline media with improved properties relevant for theapplication in the microwave range of the electromagnetic spectrum.

To solve the problem, a compound of formula U shown below is providedand a liquid crystalline medium comprising the compound.

The present invention relates to a compound of formula U

-   -   in which    -   R^(U) denotes H, alkyl or alkoxy having 1 to 12 C atoms, or        alkenyl, alkenyloxy or alkoxyalkyl having 2 to 12 C atoms, in        which one or more CH₂-groups may be replaced by

-   -    or denotes a group R^(P),    -   R^(P) denotes halogen, CN, NCS, R^(F), R^(F)—O— or R^(F)—S—,        wherein        -   R^(F) denotes fluorinated alkyl or fluorinated alkenyl            having up to 9 C atoms,    -   Z^(U1), Z^(U2) identically or differently, denote —CH═CH—,        —CF═CF—, —CH═CF—, —CF═CH—, —C≡C— or a single bond, preferably        —C≡C— or a single bond,    -   X¹, X²,    -   X³ and X⁴ identically or differently, denote Cl or F, preferably        F,    -   t is 0 or 1, and

-   -   -   denote a radical selected from the following groups:

    -   a) the group consisting of 1,4-phenylene, 1,4-naphthylene, and        2,6-naphthylene, in which one or two CH groups may be replaced        by N and in which one or more H atoms may be replaced by L,        wherein tetrafluoro-1,4-phenylene is excluded,

    -   b) the group consisting of trans-1,4-cyclohexylene,        1,4-cyclohexenylene, bicyclo[1.1.1]pentane-1,3-diyl,        4,4′-bicyclohexylene, bicyclo[2.2.2]octane-1,4-diyl,        spiro[3.3]heptane-2,6-diyl, in which one or more non-adjacent        CH₂ groups may be replaced by —O— and/or —S— and in which one or        more H atoms may be replaced by F,

    -   c) the group consisting of thiophene-2,5-diyl,        thieno[3,2-b]thiophene-2,5-diyl, selenophene-2,5-diyl, each of        which may also be mono- or polysubstituted by L,

    -   L on each occurrence, identically or differently, denotes F, Cl,        CN, SCN, SF₅ or straight-chain or branched, in each case        optionally fluorinated, alkyl, alkoxy, alkylcarbonyl,        alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1        to 12 C atoms.

The present invention further relates to a compound of formula UN

-   -   in which    -   R^(U) denotes alkyl or alkoxy having 1 to 12 C atoms, or        alkenyl, alkenyloxy or alkoxyalkyl having 3 to 12 C atoms, in        which one or more CH₂-groups may be replaced by

-   -    or denotes a group R^(P), where    -   R^(P) denotes halogen, CN, NCS, R^(F), R^(F)—O— or R^(F)—S—,        wherein R^(F) denotes fluorinated alkyl or fluorinated alkenyl        having up to 9 C atoms, and in which the other groups and        parameters have the meaning given above for formula U, and from        which the compounds

in which R^(U), X¹, X², X³, and X⁴ have the meanings given above forformula U, are excluded.

According to another aspect of the present invention there is provided aprocess for the synthesis of compounds of formula U from compounds offormula UN.

The present invention further relates to a liquid-crystalline mediumcomprising a compound of formula U and to the use of aliquid-crystalline medium comprising a compound of formula U in acomponent for high-frequency technology.

According to another aspect of the present invention there is provided acomponent and a device comprising said component, both operable in themicrowave region of the electromagnetic spectrum. Preferred componentsare phase shifters, varactors, wireless and radio wave antenna arrays,matching circuits and adaptive filters.

Preferred embodiments of the present invention are subject-matter of thedependent claims or can be taken from the description.

Surprisingly, it has been found that it is possible to achieveliquid-crystalline media having excellent stability and at the same timea high dielectric anisotropy, suitably fast switching times, a suitable,nematic phase range, high tunability and low dielectric loss, by usingcompounds of formula U in liquid-crystalline media.

The media according to the present invention are distinguished by a highclearing temperature, a broad nematic phase range and excellentlow-temperature stability (LTS). As a result, devices containing themedia are operable under extreme temperature conditions.

The media are further distinguished by high values of the dielectricanisotropy and low rotational viscosities. As a result, the thresholdvoltage, i.e. the minimum voltage at which a device is switchable, isvery low. A low operating voltage and low threshold voltage is desiredin order to enable a device having improved switching characteristicsand high energy efficiency. Low rotational viscosities enable fastswitching of the devices according to the invention.

In particular, the medium according to the invention shows improved(i.e. lower) dielectric loss.

These properties as a whole make the media particularly suitable for usein components and devices for high-frequency technology and applicationsin the microwave range, in particular devices for shifting the phase ofmicrowaves, tunable filters, tunable metamaterial structures, andelectronic beam steering antennas (e.g. phased array antennas).

Herein, “high-frequency technology” means applications ofelectromagnetic radiation having frequencies in the range of from 1 MHzto 1 THz, preferably from 1 GHz to 500 GHz, more preferably 2 GHz to 300GHz, particularly preferably from about 5 GHz to 150 GHz.

As used herein, halogen is F, Cl, Br or I, preferably F or Cl,particularly preferably F.

Herein, alkyl is straight-chain or branched and has 1 to 15 C atoms, ispreferably straight-chain and has, unless indicated otherwise, 1, 2, 3,4, 5, 6 or 7 C atoms and is accordingly preferably methyl, ethyl,n-propyl, n-butyl, n-pentyl, n-hexyl or n-heptyl.

Herein, branched alkyl is preferably isopropyl, s-butyl, isobutyl,isopentyl, 2-methylhexyl or 2-ethylhexyl.

Herein, an alkoxy radical is straight-chain or branched and contains 1to 15 C atoms. It is preferably straight-chain and has, unless indicatedotherwise, 1, 2, 3, 4, 5, 6 or 7 C atoms and is accordingly preferablymethoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, n-hexoxy or n-heptoxy.

Herein, an alkenyl radical is preferably an alkenyl radical having 2 to15 C atoms, which is straight-chain or branched and contains at leastone C—C double bond. It is preferably straight-chain and has 2 to 7 Catoms. Accordingly, it is preferably vinyl, prop-1- or -2-enyl, but-1-,-2- or -3-enyl, pent-1-, -2-, -3- or -4-enyl, hex-1-, -2-, -3-, -4- or-5-enyl, hept-1-, -2-, -3-, -4-, -5- or -6-enyl. If the two C atoms ofthe C—C double bond are substituted, the alkenyl radical can be in theform of E and/or Z isomer (trans/cis). In general, the respective Eisomers are preferred. Of the alkenyl radicals, prop-2-enyl, but-2- and-3-enyl, and pent-3- and -4-enyl are particularly preferred.

Herein, alkynyl is taken to mean an alkynyl radical having 2 to 15 Catoms, which is straight-chain or branched and contains at least one C—Ctriple bond. 1- and 2-propynyl and 1-, 2- and 3-butynyl are preferred.

In case R^(F) denotes a halogenated alkyl-, alkoxy-, alkenyl oralkenyloxy it can be branched or unbranched. Preferably it isunbranched, mono-poly or perfluorinated, preferably perfluorinated andhas 1, 2, 3, 4, 5, 6 or 7 C atoms, in case of alkenyl 2, 3, 4, 5, 6 or 7C atoms.

R^(P) preferably denotes CN, NCS, Cl, F, —(CH₂)_(n)—CH═CF₂,—(CH₂)_(n)—CH═CHF, —(CH₂)_(n)—CH═Cl₂, —C_(n)F_(2n+1), —(CF₂)_(n)—CF₂H,—(CH₂)_(n)—CF₃, —(CH₂)_(n)—CHF₂, —(CH₂)_(n)CH₂F, —CH═CF₂,—O(CH₂)_(n)—CH═CF₂, —O(CH₂)_(n)CHCl₂, —OC_(n)F_(2n+1), —O(CF₂)_(n)—CF₂H,—O(CH₂)_(n)CF₃, —O(CH₂)_(n)—CHF₂, —O(CF)_(n)CH₂F, —OCF═CF₂,—SC_(n)F_(2n+1), —S(CF)_(n)—CF₃, wherein n is an integer from 0 to 7.

The compounds of the general formula U are prepared by methods known perse, as described in the literature (for example in the standard works,such as Houben-Weyl, Methoden der organischen Chemie [Methods of OrganicChemistry], Georg-Thieme-Verlag, Stuttgart), to be precise underreaction conditions which are known and are suitable for said reactions.Use can be made here of variants which are known per se, but are notmentioned here in greater detail.

If desired, the starting materials can also be formed in situ by notisolating them from the reaction mixture, but instead immediatelyconverting them further into the compounds of the general formula U.

Preferred synthetic pathways towards compounds according to theinvention are exemplified in the schemes below, and are furtherillustrated by means of the working examples. Suitable syntheses arealso published for example in Juanli Li, Jian Li, Minggang Hu, ZhaoyiChe, Lingchao Mo, Xiaozhe Yang, Zhongwei An & Lu Zhang (2017) The effectof locations of triple bond at terphenyl skeleton on the properties ofisothiocyanate liquid crystals, Liquid Crystals, 44:9, 1374-1383 and canbe adapted to the particular desired compounds of the general formula Uby choice of suitable starting materials.

A preferred intermediate is 4-bromo-2,3,5,6-tetrafluoro-aniline whichcan be reacted to give compounds of the formula UN for example by crosscoupling reactions commonly known as Suzuki, Stille, Sonogashirareactions, and the like. Preferred pathways are exemplified in scheme 1,in which the groups and parameters have the meanings defined in claim 1.

Preferred reagents for the process according to the invention for thetransformation of compounds of the formula UN into compounds of theformula U (scheme 3) are carbon disulfide, thiophosgene, thiocarbonyldiimidazole, di-2-pyridyl thionocarbonate, bis(dimethylthiocarbamoyl)disulfide, dimethylthiocarbamoyl chloride and phenylchlorothionoformate, very preferably thiophosgene.

The reactions described should only be regarded as illustrative. Theperson skilled in the art can carry out corresponding variations of thesyntheses described and also follow other suitable synthetic routes inorder to obtain compounds of the formula U.

The compounds of formula U are preferably selected from the compounds inwhich the groups

-   -   denote

-   -   wherein

-   -    alternatively denotes

-   -    and

-   L¹ and L² identically or differently, denote F, Cl or straight chain    or branched or cyclic alkyl or alkenyl each having up to 12 C atoms,    and    where the other groups and parameters have the meanings given above.

In a preferred embodiment of the present invention, the compounds offormula U are selected from the compounds of the formulae U-1 to U-11:

-   in which-   L¹, L² and L³ identically or differently, denote H, F, Cl, methyl,    ethyl, n-propyl, isopropyl, cyclopropyl, cyclobutyl, cyclopentyl or    cyclopentenyl, and-   R^(U), X¹, X², X³ and X⁴ have the meanings given above.

According to a first aspect of the present invention there are providedcompounds of formula U in which R^(U) denotes H, alkyl or alkoxy having1 to 12 C atoms, or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 12 Catoms, in which one or more CH₂-groups may be replaced by

preferably alkyl having 1 to 12 atoms.

According to a second aspect of the present invention there are providedcompounds of formula U in which the group R^(U) denotes R^(P), whereR^(P) denotes halogen, CN, NCS, R^(F), R^(F)—O— or R^(F)—S—, and whereinR^(F) denotes fluorinated alkyl or fluorinated alkenyl having up to 9 Catoms, preferably CF₃ or OCF₃.

In a preferred embodiment of the present invention the medium comprisesone or more compounds selected from the group of compounds of theformulae I, II, and III,

-   in which-   R¹ denotes H, unfluorinated alkyl or unfluorinated alkoxy having 1    to 17, preferably 3 to 10 C atoms, or unfluorinated alkenyl,    unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to    15, preferably 3 to 10, C atoms, in which one or more CH₂-groups may    be replaced by

-    preferably unfluorinate alkyl or unfluorinate alkenyl,-   n is 0, 1 or 2,

-    to

-   -   on each occurrence, independently of one another, denote 7

-   -   in which R^(L), on each occurrence, identically or differently,        denotes H or alkyl having 1 to 6 C atoms, preferably H, methyl        or ethyl, particularly preferably H,        -   and wherein

-   -   alternatively denotes

-   -   preferably

-   -   and in case n=2, one of

-   -    preferably denotes

-   -    and the other preferably denotes

-   preferably

-    to

-   -   independently of one another, denote

-   more preferably

-    denotes

-    denotes

-    denotes

-   R² denotes H, unfluorinated alkyl or unfluorinated alkoxy having 1    to 17, preferably 3 to 10 C atoms, or unfluorinated alkenyl,    unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to    15, preferably 3 to 10, C atoms, in which one or more CH₂-groups may    be replaced by

-    preferably unfluorinated alkyl or unfluorinated alkenyl,-   Z²¹ denotes trans-CH═CH—, trans-CF═CF— or —C≡C—, preferably —C≡C— or    trans-CH═CH—, and

-   -   independently of one another, denote

-   -   -   in which R^(L), on each occurrence, identically or            differently, denotes H or alkyl having 1 to 6 C atoms,            preferably H, methyl or ethyl, particularly preferably H,        -   and wherein

-   preferably

-   -   independently of one another, denote

-   -   preferably denotes

-   -   preferably denotes

-   -   more preferably

-   R³ denotes H, unfluorinated alkyl or unfluorinated alkoxy having 1    to 17, preferably 3 to 10 C atoms, or unfluorinated alkenyl,    unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to    15, preferably 3 to 10, C atoms, in which one or more CH₂-groups may    be replaced by

-   -   preferably unfluorinated alkyl or unfluorinated alkenyl,

-   one of Z³¹ and Z³², preferably Z³²; denotes trans-CH═CH—,    trans-CF═CF— or —C≡C— and the other one, independently thereof,    denotes —C≡C—, trans-CH═CH—, trans-CF═CF— or a single bond,    preferably one of them,    -   preferably Z³², denotes —C≡C— or trans-CH═CH— and the other        denotes a single bond, and

-    to

-   -   independently of one another, denote

-   -   -   in which R^(L), on each occurrence, identically or            differently, denotes H or alkyl having 1 to 6 C atoms,            preferably H, methyl or ethyl, particularly preferably H,        -   and wherein

-    alternatively independently denotes

-   preferably

-    to

-   -   independently of one another, denote

-   more preferably

-    denotes

-    denotes

-   -   in particular

-    denotes

-   -   in particular

In the compounds of the formulae I, II and III, R^(L) preferably denotesH.

In another preferred embodiment, in the compounds of formulae I, II andIII, one or two groups R^(L), preferably one group R^(L) is differentfrom H.

In a preferred embodiment of the present invention, the compounds offormula I are selected from the group of compounds of the formulae I-1to I-5:

in whichL¹, L² and L³ on each occurrence, identically or differently, denote Hor F, and the other groups have the respective meanings indicated abovefor formula I andpreferably

-   R¹ denotes unfluorinated alkyl having 1 to 7 C atoms or    unfluorinated alkenyl having 2 to 7 C atoms.

The media preferably comprise one or more compounds of formula I-1,which are preferably selected from the group of the compounds of theformulae I-1a to I-1d, preferably of formula I-1b:

in which R¹ has the meaning indicated above for formula I and preferablydenotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinatedalkenyl having 2 to 7 C atoms.

The media preferably comprise one or more compounds of formula I-2,which are preferably selected from the group of the compounds of theformulae I-2a to I-2e, preferably of formula I-2c:

in which R¹ has the meaning indicated above for formula I and preferablydenotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinatedalkenyl having 2 to 7 C atoms.

The media preferably comprise one or more compounds of formula I-3,which are preferably selected from the group of the compounds of theformulae I-3a to I-3d, particularly preferably of formula I-3b:

in which R¹ has the meaning indicated above for formula I and preferablydenotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinatedalkenyl having 2 to 7 C atoms.

The media preferably comprise one or more compounds of formula I-4,which are preferably selected from the group of the compounds of theformulae I-4a to I-4e, particularly preferably of formula I-4b:

in which R¹ has the meaning indicated above for formula I and preferablydenotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinatedalkenyl having 2 to 7 C atoms.

The media preferably comprise one or more compounds of formula I-5,which are preferably selected from the group of the compounds of theformulae I-5a to I-5d, particularly preferably of formula I-5b:

in which R¹ has the meaning indicated above for formula I and preferablydenotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinatedalkenyl having 2 to 7 C atoms.

The media preferably comprise one or more compounds of formula II, whichare preferably selected from the group of the compounds of the formulaeII-1 to II-3, preferably selected from the group of the compounds of theformulae II-1 and II-2:

in which the occurring groups have the meanings given under formula IIabove and

-   preferably-   R² denotes H, unfluorinated alkyl or alkoxy having 1 to 7 C atoms or    unfluorinated alkenyl having 2 to 7 C atoms,-   and one of

-    denotes

-   -   and the other, independently denotes

-   -   preferably

-   -   most preferably

-   and preferably-   R² denotes C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   n denotes an integer in the range from 1 to 7, preferably in the    range from 2 to 6 and particularly preferably 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The compounds of formula II-1 are preferably selected from the group ofthe compounds of the formulae II-1a to II-1e:

-   in which-   R² has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   n denotes an integer in the range from 1 to 7, preferably in the    range from 2 to 6 and particularly preferably 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The compounds of formula II-2 are preferably selected from the group ofthe compounds of the formulae II-2a and II-2b:

-   in which-   R² has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z),-   n denotes an integer in the range from 1 to 7, preferably in the    range from 2 to 6 and particularly preferably 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The compounds of formula II-3 are preferably selected from the group ofthe compounds of the of formulae II-3a to II-3d:

-   in which-   R² has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z),-   n denotes an integer in the range from 1 to 7, preferably in the    range from 2 to 6 and particularly preferably 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The compounds of formula III are preferably selected from the group ofthe compounds of the formulae III-1 to III-6, more preferably of theformulae selected from the group of the compounds of the formulae III-1,III-2, III-3 and III-4, and particularly preferably of formula III-1and/or III-2:

-   in which-   Z³¹ and Z³² independently of one another denote trans-CH═CH— or    trans-CF═CF—, preferably trans-CH═CH—, and in formula III-6    alternatively one of Z³¹ and Z³² may denote —C≡C— and the other    groups have the meaning given above under formula III,-   and preferably-   R³ denotes H, unfluorinated alkyl or alkoxy having 1 to 7 C atoms or    unfluorinated alkenyl having 2 to 7 C atoms,-   and one of

-    preferably

-    denotes

-   -   preferably

-   -   and the others, independently of one another, denote

-   -   preferably

-   -   more preferably

-   where

-    alternatively denotes

-   and preferably-   R³ denotes C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z),-   n denotes an integer in the range from 1 to 7, preferably in the    range from 2 to 6 and particularly preferably 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The compounds of formula III-1 are preferably selected from the group ofthe compounds of the formulae III-1a to III-1k, more preferably selectedfrom the group of the compounds of the formulae III-1a, III-1b, III-1gand III-1h, particularly preferably of formula III-1b and/or III-1h:

-   in which-   R³ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z),-   n denotes an integer in the range from 1 to 7, preferably in the    range from 2 to 6 and particularly preferably 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The compounds of formula III-2 are preferably compounds of formulaIII-2a to III-2l, very preferably III-2b and/or III-2j:

-   in which-   R³ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z),-   n denotes an integer in the range from 1 to 7, preferably in the    range from 2 to 6 and particularly preferably 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The compounds of formula III-5 are preferably selected from thecompounds of formula III-5a:

-   R³ has the meaning indicated above for formula III-5 and preferably    denotes C_(n)H_(2n+1), in which-   n denotes an integer in the range from 1 to 7, preferably in the    range from 2 to 6 and particularly preferably 3 to 5.

In a preferred embodiment, the media according to the invention compriseone or more compounds selected from the group of compounds of theformulae IIA-1-1 to IIA-1-12, very preferably IIA-1-1 or IIA-1-2:

-   in which-   R¹ denotes alkyl or alkenyl having up to 7 C atoms, preferably    ethyl, n-propyl, n-butyl or n-pentyl, n-hexyl,-   R^(L) on each occurrence, the same or differently, denotes alkyl or    alkenyl having 1 to 5 C atoms, or cycloalkyl or cycloalkenyl each    having 3 to 6 C atoms, preferably methyl, ethyl, n-propyl, n-butyl,    isopropyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclopent-1-enyl,    very preferably ethyl,    and from which the compounds of formula II-1 are excluded.

Additionally, the liquid-crystalline media according to the presentinvention in a certain embodiment, which may be the same or differentfrom the previous preferred embodiments preferably comprise one or morecompounds of formula IV,

-   in which

-    denotes

-   -   s is 0 or 1, preferably 1, and

-   preferably

-    denotes

-   particularly preferably

-   L⁴ denotes H or alkyl having 1 to 6 C atoms, cycloalkyl having 3 to    6 C atoms or cycloalkenyl having 4 to 6 C atoms, preferably CH₃,    C₂H₅, n-C₃H₇, i-C₃H₇, cyclopropyl, cyclobutyl, cyclohexyl,    cyclopent-1-enyl or cyclohex-1-enyl, and particularly preferably    CH₃, C₂H₅, cyclopropyl or cyclobutyl,-   X⁴ denotes H, alkyl having 1 to 3 C atoms or halogen, preferably H,    F or Cl, more preferably H or F and very particularly preferably F,-   R⁴¹ to R⁴⁴, independently of one another, denote unfluorinated alkyl    or unfluorinated alkoxy, each having 1 to 15 C atoms, unfluorinated    alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl, each    having 2 to 15 C atoms, or cycloalkyl, alkylcycloalkyl,    cycloalkenyl, alkylcycloalkenyl, alkylcycloalkylalkyl or    alkylcycloalkenylalkyl, each having up to 15 C atoms, and    alternatively one of R⁴³ and R⁴⁴ or both also denote H,-   preferably-   R⁴¹ and R⁴², independently of one another, denote unfluorinated    alkyl or unfluorinated alkoxy, each having 1 to 7 C atoms, or    unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated    alkoxyalkyl, each having 2 to 7 C atoms,-   particularly preferably-   R⁴¹ denotes unfluorinated alkyl having 1 to 7 C atoms or    unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated    alkoxyalkyl, each having 2 to 7 C atoms, and-   particularly preferably-   R⁴² denotes unfluorinated alkyl or unfluorinated alkoxy, each having    1 to 7 C atoms, and-   preferably-   R⁴³ and R⁴⁴ denote H, unfluorinated alkyl having 1 to 5 C atoms,    unfluorinated cycloalkyl or cycloalkenyl having 3 to 7 C atoms,    unfluorinated alkylcyclohexyl or unfluorinated cyclohexylalkyl, each    having 4 to 12 C atoms, or unfluorinated alkylcyclohexylalkyl having    5 to 15 C atoms, particularly preferably cyclopropyl, cyclobutyl or    cyclohexyl, and very particularly preferably at least one of R⁴³ and    R⁴⁴ denotes n-alkyl, particularly preferably methyl, ethyl or    n-propyl, and the other denotes H or n-alkyl, particularly    preferably H, methyl, ethyl or n-propyl.

In a preferred embodiment of the present invention, the liquid-crystalmedium additionally comprises one or more compounds selected from thegroup of compounds of the formulae V, VI, VII, VIII and IX:

-   in which-   L⁵¹ denotes R⁵¹ or X⁵¹,-   L⁵² denotes R⁵² or X⁵²,-   R⁵¹ and R⁵², independently of one another, denote H, unfluorinated    alkyl or unfluorinated alkoxy having 1 to 17, preferably 3 to 10, C    atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or    unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C    atoms, preferably alkyl or unfluorinated alkenyl,-   X⁵¹ and X⁵², independently of one another, denote H, F, Cl, —CN,    SF₅, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms    or fluorinated alkenyl, fluorinated alkenyloxy or fluorinated    alkoxyalkyl having 2 to 7 C atoms, preferably fluorinated alkoxy,    fluorinated alkenyloxy, F or Cl, and

-   -   independently of one another, denote

-   -   preferably

-   L⁶¹ denotes R⁶¹ and, in the case where Z⁶¹ and/or Z⁶² denote    trans-CH═CH— or trans-CF═CF—, alternatively also denotes X⁶¹,-   L⁶² denotes R⁶² and, in the case where Z⁶¹ and/or Z⁶² denote    trans-CH═CH— or trans-CF═CF—, alternatively also denotes X⁶²,-   R⁶¹ and R⁶², independently of one another, denote H, unfluorinated    alkyl or unfluorinated alkoxy having 1 to 17, preferably 3 to 10, C    atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or    unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C    atoms, preferably alkyl or unfluorinated alkenyl,-   X⁶¹ and X⁶², independently of one another, denote F or Cl, —CN, SF₅,    fluorinated alkyl or alkoxy having 1 to 7 C atoms or fluorinated    alkenyl, alkenyloxy or alkoxyalkyl having 2 to 7 C atoms,-   one of Z⁶¹ and Z⁶² denotes trans-CH═CH—, trans-CF═CF— or —C≡C— and    the other, independently thereof, denotes trans-CH═CH—, trans-CF═CF—    or a single bond, preferably one of them denotes —C≡C— or    trans-CH═CH— and the other denotes a single bond, and

-    to

-   -   independently of one another, denote

-   -   preferably

-   and-   x denotes 0 or 1;-   L⁷¹ denotes R⁷¹ or X⁷¹,-   L⁷² denotes R⁷² or X⁷²,-   R⁷¹ and R⁷², independently of one another, denote H, unfluorinated    alkyl or unfluorinated alkoxy having 1 to 17, preferably 3 to 10, C    atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or    unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C    atoms, preferably alkyl or unfluorinated alkenyl,-   X⁷¹ and X⁷², independently of one another, denote H, F, Cl, —CN,    —NCS, —SF₅, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C    atoms or fluorinated alkenyl, unfluorinated or fluorinated    alkenyloxy or unfluorinated or fluorinated alkoxyalkyl having 2 to 7    C atoms, preferably fluorinated alkoxy, fluorinated alkenyloxy, F or    Cl, and-   Z⁷¹ to Z⁷³, independently of one another, denote trans-CH═CH—,    trans-CF═CF—, —C≡C— or a single bond, preferably one or more of them    denote a single bond, particularly preferably all denote a single    bond and

-    to

-   -   independently of one another, denote

-   -   preferably

-   R⁸¹ and R⁸², independently of one another, denote H, unfluorinated    alkyl or alkoxy having 1 to 15, preferably 3 to 10, C atoms or    unfluorinated alkenyl, alkenyloxy or alkoxyalkyl having 2 to 15,    preferably 3 to 10, C atoms, preferably unfluorinated alkyl or    alkenyl, one of-   Z⁸¹ and Z⁸² denotes trans-CH═CH—, trans-CF═CF— or —C≡C— and the    other, independently thereof, denotes trans-CH═CH—, trans-CF═CF— or    a single bond, preferably one of them denotes —C≡C— or trans-CH═CH—    and the other denotes a single bond, and

-    denotes

-   -   independently of one another, denote

-   L⁹¹ denotes R⁹¹ or X⁹¹,-   L⁹² denotes R⁹² or X⁹²,-   R⁹¹ and R⁹², independently of one another, denote H, unfluorinated    alkyl or alkoxy having 1 to 15, preferably 3 to 10, C atoms or    unfluorinated alkenyl, alkenyloxy or alkoxyalkyl having 2 to 15,    preferably 3 to 10, C atoms, preferably unfluorinated alkyl or    alkenyl,-   X⁹¹ and X⁹², independently of one another, denote H, F, Cl, —CN,    —NCS, —SF₅, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C    atoms or fluorinated alkenyl, unfluorinated or fluorinated    alkenyloxy or unfluorinated or fluorinated alkoxyalkyl having 2 to 7    C atoms, preferably fluorinated alkoxy, fluorinated alkenyloxy, F or    Cl, and-   Z⁹¹ to Z⁹³, independently of one another, denote trans-CH═CH—,    trans-CF═CF—, —C≡C— or a single bond, preferably one or more of them    denotes a single bond, and particularly preferably all denote a    single bond,

-    denotes

-    to

-   -   independently of one another, denote

In a preferred embodiment of the present invention, the liquid-crystalmedium comprises one or more compounds of the formula V, preferablyselected from the group of the compounds of the formulae V-1 to V-3,preferably of the formulae V-1 and/or V-2 and/or V-3, preferably of theformulae V-1 and V-2:

in which the occurring groups have the respective meanings indicatedabove for formula V and preferably

-   R⁵¹ denotes unfluorinated alkyl having 1 to 7 C atoms or    unfluorinated alkenyl having 2 to 7 C atoms,-   R⁵² denotes unfluorinated alkyl having 1 to 7 C atoms or    unfluorinated alkenyl having 2 to 7 C atoms or unfluorinated alkoxy    having 1 to 7 C atoms,-   X⁵¹ and X⁵², independently of one another, denote F, Cl, —OCF₃,    —CF₃, —CN or —SF₅, preferably F, Cl, —OCF₃ or —CN.

The compounds of the formula V-1 are preferably selected from the groupof the compounds of the formulae V-1a to V-1d, preferably V-1c and V-1d

in which the parameters have the respective meanings indicated above forformula V-1 and in which

-   Y⁵¹ and Y⁵², in each case independently of one another, denote H or    F, and preferably-   R⁵¹ denotes alkyl or alkenyl having up to 7 C atoms, and-   X⁵¹ denotes F, Cl or —OCF₃.

The compounds of the formula V-2 are preferably selected from the groupof the compounds of the formulae V-2a to V-2e and/or from the group ofthe compounds of the formulae V-2f and V-2g:

where in each case the compounds of the formula V-2a are excluded fromthe compounds of the formulae V-2b and V-2c, the compounds of theformula V-2b are excluded from the compounds of the formula V-2c and thecompounds of the formula V-2f are excluded from the compounds of theformula V-2g, andin which the parameters have the respective meanings indicated above forformula V-1 and in which

-   Y⁵¹ and Y⁵², in each case independently of one another, denote H or    F, and preferably-   Y⁵¹ and Y⁵² denotes H and the other denotes H or F, preferably    likewise denotes H.

The compounds of the formula V-3 are preferably compounds of the formulaV-3a:

in which the parameters have the respective meanings indicated above forformula V-1 and in which preferably

-   X⁵¹ denotes F, Cl, preferably F,-   X⁵² denotes F, Cl or —OCF₃, preferably —OCF₃.

The compounds of the formula V-1a are preferably selected from the groupof the compounds of the formulae V-1a-1 and V-1a-2:

in which

-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1), in which-   n denotes an integer in the range from 1 to 7, preferably in the    range from 2 to 6 and particularly preferably 3 to 5.

The compounds of the formula V-1b are preferably compounds of theformula V-1b-1:

in which

-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1), in which-   n denotes an integer in the range from 1 to 7, preferably in the    range from 2 to 6 and particularly preferably from 3 to 5.

The compounds of the formula V-1c are preferably selected from the groupof the compounds of the formulae V-1c-1 to V-1c-4, particularlypreferably selected from the group of the compounds of the formulaeV-1c-1 and V-1c-2:

-   in which-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1), in which-   n denotes an integer in the range from 1 to 7, preferably in the    range from 2 to 6 and particularly preferably 3 to 5.

The compounds of the formula V-1d are preferably selected from the groupof the compounds of the formulae V-1d-1 and V-1d-2, particularlypreferably the compound of the formula V-1d-2:

-   in which-   R^(S1) has the meaning indicated above and preferably denotes    C_(n)H_(2n+1), in which-   n denotes an integer in the range from 1 to 7, preferably in the    range from 2 to 6 and particularly preferably 3 to 5.

The compounds of the formula V-2a are preferably selected from the groupof the compounds of the formulae V-2a-1 and V-2a-2, particularlypreferably the compounds of the formula V-2a-1:

-   in which-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁵² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

Preferred combinations of (R⁵¹ and R⁵²), in particular in the case offormula V-2a-1, are (C_(n)H_(2n+1) and C_(m)H_(2m+1)), (C_(n)H_(2n+1)and O—C_(m)H_(2m+1)), (CH₂═CH—(CH₂)_(z) and C_(m)H_(2m+1)),(CH₂═CH—(CH₂)_(z) and O—C_(m)H_(2m+1)) and (C_(n)H_(2n+1) and(CH₂)_(z)—CH═CH₂).

Preferred compounds of the formula V-2b are the compounds of the formulaV-2b-1:

-   in which-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁵² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combination of (R⁵¹ and R⁵²) here is, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)).

Preferred compounds of the formula V-2c are the compounds of the formulaV-2c-1:

-   in which-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁵² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combination of (R⁵¹ and R⁵²) here is, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)).

Preferred compounds of the formula V-2d are the compounds of the formulaV-2d-1:

-   in which-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁵² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combination of (R⁵¹ and R⁵²) here is, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)).

Preferred compounds of the formula V-2e are the compounds of the formulaV-2e-1:

-   in which-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁵² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combination of (R⁵¹ and R⁵²) here is, in particular,(C_(n)H_(2n+1) and O—C_(m)H_(2m+1)).

Preferred compounds of the formula V-2f are the compounds of the formulaV-2f-1:

-   in which-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁵² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁵¹ and R⁵²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andC_(m)H_(2m+1)).

Preferred compounds of the formula V-2g are the compounds of the formulaV-2g-1:

-   in which-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁵² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁵¹ and R⁵²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)).

The compounds of the formula VI are preferably selected from the groupof the compounds of the formulae VI-1 to VI-5:

-   in which-   Z⁶¹ and Z⁶² denote —C≡C—, trans-CH═CH— or trans-CF═CF—, preferably    —C≡C— or trans-CH═CH—, and the other occurring groups and parameters    have the meaning given above under formula VI,-   and preferably-   R⁶¹ and R⁶², independently of one another, denote H, unfluorinated    alkyl or alkoxy having 1 to 7 C atoms or unfluorinated alkenyl    having 2 to 7 C atoms,-   X⁶² denotes F, Cl, —OCF₃ or —CN,

The compounds of the formula VI-1 are preferably selected from the groupof the compounds of the formulae VI-1a and VI-1b, more preferablyselected from compounds of the formula VI-1a:

-   in which-   R⁶¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁶² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁶¹ and R⁶²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), in the case of formula VI-1a particularly preferably(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and in the case of formula VI-1bparticularly preferably (C_(n)H_(2n+1) and O—C_(m)H_(2m+1)).

The compounds of the formula VI-3 are preferably selected from thecompounds of the formula VI-3a to VI-3e:

in which the parameters have the meaning given above under formula VI-3and preferably

-   R⁶¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1), in which-   n denotes an integer in the range from 1 to 7, preferably in the    range from 2 to 6 and particularly preferably from 3 to 5, and-   X⁶² denotes —F, —Cl, —OCF₃, or —CN.

The compounds of the formula VI-4 are preferably selected from compoundsof the formulae VI-4a to VI-4e:

in which the parameters have the meaning given above under formula VI-4and preferably

-   R⁶¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1), in which-   n denotes an integer in the range from 1 to 7, preferably in the    range from 2 to 6 and particularly preferably from 3 to 5, and-   X⁶² denotes F, Cl, OCF₃, or —CN.

The compounds of the formula VI-5 are preferably selected from thecompounds of the formulae VI-5a to VI-5d, preferably VI-5b:

in which the parameters have the meaning given above under formula VI-5and preferably

-   R⁶¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1), in which-   n denotes an integer in the range from 1 to 7, preferably in the    range from 2 to 6 and particularly preferably from 3 to 5, and-   X⁶² denotes —F, —Cl, —OCF₃, or —CN, particularly preferably —OCF₃.

The compounds of the formula VII are preferably selected from the groupof the compounds of the formulae VII-1 to VII-6:

where the compounds of the formula VII-5 are excluded from the compoundsof the formula VII-6, and

-   in which the parameters have the respective meanings indicated above    for formula VII,-   Y⁷¹, Y⁷², Y⁷³ independently from one another, denote H or F,-   and preferably-   R⁷¹ denotes unfluorinated alkyl or alkoxy, each having 1 to 7 C    atoms, or unfluorinated alkenyl having 2 to 7 C atoms,-   R⁷² denotes unfluorinated alkyl or alkoxy, each having 1 to 7 C    atoms, or unfluorinated alkenyl having 2 to 7 C atoms,-   X⁷² denotes F, Cl; NCS or —OCF₃, preferably F or NCS, and-   particularly preferably-   R⁷¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁷² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 15, preferably in the range from 2 to 6 and    particularly preferably from 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The compounds of the formula VII-1 are preferably selected from thegroup of the compounds of the formulae VII-1a to VII-1 d:

-   in which X⁷² has the meaning given above for formula VII-2 and-   R⁷¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1), in which-   n denotes 1 to 7, preferably 2 to 6, particularly preferably 2, 3 or    5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2, and-   X⁷² preferably denotes F.

The compounds of the formula VII-2 are preferably selected from thegroup of the compounds of the formulae VII-2a and VII-2b, particularlypreferably of the formula VII-2a:

-   in which-   R⁷¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁷² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably from 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁷¹ and R⁷²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andC_(m)H_(2m+1)).

The compounds of the formula VII-3 are preferably compounds of theformula VII-3a:

-   in which-   R⁷¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁷² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably from 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁷¹ and R⁷²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andC_(m)H_(2m+1)).

The compounds of the formula VII-4 are preferably compounds of theformula VII-4a:

-   in which-   R⁷¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁷² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably from 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁷¹ and R⁷²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andC_(m)H_(2m+1)).

The compounds of the formula VII-5 are preferably selected from thegroup of the compounds of the formulae VII-5a and VII-5b, morepreferably of the formula VII-5a:

-   in which-   R⁷¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁷² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably from 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁷¹ and R⁷²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andC_(m)H_(2m+1)).

The compounds of the formula VII-6 are preferably selected from thegroup of the compounds of the formulae VII-6a and VII-6b:

-   in which-   R⁷¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁷² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably from 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁷¹ and R⁷²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andC_(m)H_(2m+1)).

The compounds of the formula VII-7 are preferably selected from thegroup of the compounds of the formulae VII-7a to VII-7d:

-   in which-   R⁷¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z),-   X⁷² denotes F, —OCF₃ or —NCS,-   n denotes an integer in the range from 1 to 7, preferably in the    range from 2 to 6 and particularly preferably from 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The compounds of the formula VIII are preferably selected from the groupof the compounds of the formulae VIII-1 to VIII-3, more preferably thesecompounds of the formula VIII predominantly consist, even morepreferably essentially consist and very particularly preferablycompletely consist thereof:

-   in which-   one of Y⁸¹ and Y⁸² denotes H and the other denotes H or F, and-   R⁸¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁸² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably from 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁸¹ and R⁸²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andC_(m)H_(2m+1)).

The compounds of the formula VIII-1 are preferably selected from thegroup of the compounds of the formulae VIII-1a to VIII-1c:

-   in which-   R⁸¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁸² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably from 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁸¹ and R⁸²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andC_(m)H_(2m+1)).

The compounds of the formula VIII-2 are preferably compounds of theformula VIII-2a:

-   in which-   R⁸¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁸² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably from 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁸¹ and R⁸²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)), (C_(n)H_(2n+1) and O—C_(m)H_(2m+1))and (CH₂═CH—(CH₂)_(z) and C_(m)H_(2m+1)), particularly preferably(C_(n)H_(2n+1) and C_(m)H_(2m+1)).

The compounds of the formula VIII-3 are preferably compounds of theformula VIII-3a:

-   in which-   R⁸¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁸² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably from 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁸¹ and R⁸²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)).

The compounds of the formula IX are preferably selected from the groupof the compounds of the formulae IX-1 to IX-3:

in which the parameters have the respective meaning indicated aboveunder formula IX and preferably

-   one of

-    to

-   -   denotes

-   and-   in which-   R⁹¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁹² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably from 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁹¹ and R⁹²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)).

The compounds of the formula IX-1 are preferably selected from the groupof the compounds of the formulae IX-1a to IX-1e:

-   in which the parameters have the meaning given above and preferably-   R⁹¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1), and-   n denotes an integer in the range from 1 to 7, preferably in the    range from 2 to 6 and particularly preferably from 3 to 5, and-   X⁹² preferably denotes F or Cl.

The compounds of the formula IX-2 are preferably selected from the groupof the compounds of the formulae IX-2a and IX-2b:

-   in which-   R⁹¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁹² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably from 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combination of (R⁹¹ and R⁹²) here is, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)).

The compounds of the formula IX-3 are preferably compounds of theformulae IX-3a and IX-3b:

-   in which-   R⁹¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁹² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 1 to 7, preferably in the range from 2 to 6 and    particularly preferably from 3 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁹¹ and R⁹²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)).

In a preferred embodiment of the present invention the medium comprisesone or more compounds of formula X

-   in which-   R¹⁰¹ denotes H, alkyl or alkoxy having 1 to 15, preferably 3 to 10,    C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or    unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C    atoms, preferably alkyl or alkenyl,-   X¹⁰¹ denotes H, F, Cl, —CN, SF₅, NCS, fluorinated alkyl or    fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl,    fluorinated alkenyloxy or fluorinated alkoxyalkyl having 2 to 7 C    atoms, preferably fluorinated alkoxy, fluorinated alkenyloxy, F, Cl    or NCS, particularly preferably NCS,-   Y¹⁰¹ denotes methyl, ethyl or Cl,-   Y¹⁰² denotes H, methyl, ethyl, F or Cl, preferably H or F,-   Z¹⁰¹, Z¹⁰² identically or differently, denote a single bond,    —CH═CH—, —CF═CF— or —C≡C—,

-    independently of one another, denote

-   -   preferably

-   and where

-    alternatively denotes

-    and-   n is 0 or 1.

Preferably, the compounds of formula X are selected from thesub-formulae X-1 and X-2

in which the occurring groups and parameters have the meanings givenabove for formula X.

Particularly preferably, the media according to the invention compriseone or more compounds selected from the group of compounds of theformulae X-1-1 to X-1-9

In a preferred embodiment, the medium according to the inventioncomprises one or more compounds of formula XI

-   -   in which    -   R^(S) denotes H, alkyl or alkoxy having 1 to 12 C atoms, or        alkenyl, alkenyloxy or alkoxyalkyl having 2 to 12 C atoms, in        which one or more CH₂-groups may be replaced by

-   -    and in which one or more H atoms may be replaced by F,

-   -    on each occurrence, independently of one another,

-   -   in which R^(L), on each occurrence identically or differently,        denotes H, Cl or straight chain, branched or cyclic alkyl having        1 to 6 C atoms,    -   L^(S1), L^(S2) identically or differently, denote H, Cl or F,    -   R^(S1), R^(S2), identically or differently, denote H, alkyl or        alkenyl, having up to 6 C atoms, or cyclopropyl, cyclobutyl,        cyclopentenyl, or cyclopentyl,    -   R^(Th1), R^(Th2) identically or differently, denote H, alkyl or        alkenyl or alkoxy, having up to 6 C atoms, or cyclopropyl,        cyclobutyl, cyclopentenyl or cyclopentyl,    -   Z^(S1), Z^(S2), Z^(S3) identically or differently, denote        —CH═CH—, —CH═CF—, —CF═CH—, —CF═CF—, —C≡C—, or a single bond,    -   a, b identically or differently, are 0 or 1.

Preferably, the compounds of formula XI are selected from the group ofcompounds of the formulae XI-1 to XI-24:

in which the occurring groups have the meanings given above for formulaXI and preferably

-   R^(S) denotes alkyl or alkenyl having 2 to 6 C atoms, in which one    or more CH₂-groups may be replaced by

-   R^(S1) and R^(S2) identically or differently, denote H or alkyl    having 1 to 6 C atoms, preferably H,-   R^(S3) denotes H, F or alkyl, having up to 6 C atoms, or    cyclopropyl, preferably H, F or ethyl, very preferably H,-   L^(S1) and L^(S2) identically or differently, denote H or F,    preferably F.

Preferably, the medium according to the invention comprises one or morecompounds of formula T

-   in which-   R^(T) denotes halogen, CN, NCS, R^(F), R^(F)—O— or R^(F)—S—, wherein    R^(F) denotes fluorinated alkyl or fluorinated alkenyl having up to    12 C atoms,

-   -   on each occurrence, independently of one another, denote

-   L⁴ and L⁵ identically or differently, denote F, Cl or straight chain    or branched or cyclic alkyl or alkenyl each having up to 12 C atoms;-   Z^(T3), Z^(T4) identically or differently, denote —CH═CH—, —CF═CF—,    —CH═CF—, —CF═CH—, —C≡C— or a single bond, and-   t is 0 or 1.

In a preferred embodiment, the liquid crystalline media according to theinvention comprise one or more compounds selected from the group ofcompounds of the formulae T-1a to T-3b below:

-   in which

-    and have the meanings given above and-   n is 1, 2, 3, 4, 5, 6 or 7, preferably 1, 2, 3 or 4, particularly    preferably 1.

In a particularly preferred embodiment of the present invention themedia comprise one or more compounds selected from the compounds of theformulae T-1a and T-2a.

Preferred compounds of formula T-1a are selected from the group ofcompounds of the following sub-formulae:

in which n is 1, 2, 3 or 4, preferably 1.

Preferred compounds of formula T-2a are selected from the group ofcompounds of the following sub-formulae:

in which n is 1, 2, 3 or 4, preferably 1.

Very preferably, the medium according to the invention comprises one ormore compounds of formula T-1a-5.

In an embodiment, the medium according to the invention comprises one ormore compounds of formula I, II, III, IV, V, VI, VII, VIII, IX, X inwhich the radical R¹, R², R³, R⁴¹, R⁴², R⁵¹, R⁵², R⁶¹, R⁶², R⁷¹, R⁷²,R⁸¹, R⁸², R⁹¹, R⁹², R¹⁰¹, R¹⁰² and R^(S), respectively, is a cyclicalkyl group.

As used herein, cyclic alkyl is taken to mean straight chain or branchedalkyl or alkenyl having up to 12 C atoms, preferably alkyl having 1 to 7C atoms, in which a group CH₂ is replaced with a carbocyclic ring having3 to 5 C atoms, very preferably selected from the group consisting ofcyclopropylalkyl, cyclobutylalkyl, cyclopentylalkyl andcyclopentenylalkyl.

Very preferred compounds comprising a cyclic alkyl group are selectedfrom the compounds of the formulae Cy-1 to Cy-14

The media according to the present invention comprise one or more chiraldopants. Preferably these chiral dopants have an absolute value of thehelical twisting power (HTP) in the range of from 1 μm⁻¹ to 150 μm⁻¹,preferably in the range of from 10 μm⁻¹ to 100 μm⁻¹. In case the mediacomprise two or more chiral dopants, these may have opposite signs oftheir HTP-values. This condition is preferred for some specificembodiments, as it allows to compensate the chirality of the respectivecompounds to some degree and, thus, may be used to compensate varioustemperature dependent properties of the resulting media in the devices.Generally, however, it is preferred that most, preferably all of thechiral compounds present in the media according to the present inventionhave the same sign of their HTP-values.

Preferably the chiral dopants present in the media according to theinstant application are mesogenic compounds and most preferably theyexhibit a mesophase on their own.

In a preferred embodiment of the present invention, the medium comprisestwo or more chiral compounds which all have the same algebraic sign ofthe HTP.

The temperature dependence of the HTP of the individual compounds may behigh or low. The temperature dependence of the pitch of the medium canbe compensated by mixing compounds having different temperaturedependencies of the HTP in corresponding ratios.

For the optically active component, a multitude of chiral dopants, someof which are commercially available, is available to the person skilledin the art, such as, for example, cholesteryl nonanoate, R- and S-811,R- and S-1011, R- and S-2011, R- and S-3011, R- and S-4011, or CB15 (allMerck KGaA, Darmstadt).

Particularly suitable dopants are compounds which contain one or morechiral groups and one or more mesogenic groups, or one or more aromaticor alicyclic groups which form a mesogenic group with the chiral group.

Suitable chiral groups are, for example, chiral branched hydrocarbonradicals, chiral ethane diols, binaphthols or dioxolanes, furthermoremono- or polyvalent chiral groups selected from the group consisting ofsugar derivatives, sugar alcohols, sugar acids, lactic acids, chiralsubstituted glycols, steroid derivatives, terpene derivatives, aminoacids or sequences of a few, preferably 1-5, amino acids.

Preferred chiral groups are sugar derivatives, such as glucose, mannose,galactose, fructose, arabinose and dextrose; sugar alcohols, such as,for example, sorbitol, mannitol, iditol, galactitol or anhydroderivatives thereof, in particular dianhydrohexitols, such asdianhydrosorbide (1,4:3,6-dianhydro-D-sorbide, isosorbide),dianhydromannitol (isosorbitol) or dianhydroiditol (isoiditol); sugaracids, such as, for example, gluconic acid, gulonic acid and ketogulonicacid; chiral substituted glycol radicals, such as, for example, mono- oroligoethylene or propylene glycols, in which one or more CH₂ groups aresubstituted by alkyl or alkoxy; amino acids, such as, for example,alanine, valine, phenylglycine or phenylalanine, or sequences of from 1to 5 of these amino acids; steroid derivatives, such as, for example,cholesteryl or cholic acid radicals; terpene derivatives, such as, forexample, menthyl, neomenthyl, campheyl, pineyl, terpineyl,isolongifolyl, fenchyl, carreyl, myrthenyl, nopyl, geraniyl, linaloyl,neryl, citronellyl or dihydrocitronellyl.

The media according to the present invention preferably comprise chiraldopants which are selected from the group of known chiral dopants.Suitable chiral groups and mesogenic chiral compounds are described, forexample, in DE 34 25 503, DE 35 34 777, DE 35 34 778, DE 35 34 779 andDE 35 34 780, DE 43 42 280, EP 01 038 941 and DE 195 41 820. Examplesare also compounds listed in Table F below.

Chiral compounds preferably used according to the present invention areselected from the group consisting of the formulae shown below.

Particular preference is given to chiral dopants selected from the groupconsisting of compounds of the following formulae A-I to A-III and A-Ch:

-   in which-   R^(a11), R^(a12) and R^(b12), independently of one another, denote    alkyl having 1 to 15 C atoms, in which, in addition, one or more    non-adjacent CH₂ groups may each be replaced, independently of one    another, by —C(R^(z))═C(R^(z))—, —C≡C—, —O—, —S—, —CO—, —CO—O—,    —O—CO— or —O—CO—O— in such a way that O and/or S atoms are not    linked directly to one another, and in which, in addition, one or    more H atoms may each be replaced by F, Cl, Br, I or CN, preferably    alkyl, more preferably n-alkyl, with the proviso that R^(a12) is    different from R^(b12)-   R^(a21) and R^(a22), independently of one another, denote alkyl    having 1 to 15 C atoms, in which, in addition, one or more    non-adjacent CH₂ groups may each be replaced, independently of one    another, by —C(R^(z))═C(R^(z))—, —C≡C—, —O—, —S—, —CO—, —CO—O—,    —O—CO— or —O—CO—O— in such a way that O and/or S atoms are not    linked directly to one another, and in which, in addition, one or    more H atoms may be replaced by F, Cl, Br, I or CN, preferably both    are alkyl, more preferably n-alkyl,-   R^(a31), R^(a32) and R^(b32), independently of one another, denote    straight-chain or branched alkyl having 1 to 15 C atoms, in which,    in addition, one or more non-adjacent CH₂ groups may each be    replaced, independently of one another, by —C(R^(z))═C(R^(z))—,    —C≡C—, —O—, —S—, —CO—, —CO—O—, —O—CO— or —O—CO—O— in such a way that    O and/or S atoms are not linked directly to one another, and in    which, in addition, one or more H atoms may be replaced by F, Cl,    Br, I or CN, preferably alkyl, more preferably n-alkyl, with the    proviso that R^(a32) is different from R^(b32);-   R^(z) denotes H, CH₃, F, Cl, or CN, preferably H or F,-   R⁸ has one of the meanings of R^(a11) given above, preferably alkyl,    more preferably n-alkyl having 1 to 15 C atoms,-   Z⁸ denotes —C(O)O—, CH₂O, CF₂O or a single bond, preferably —C(O)O—,    -   A¹¹ is defined as A¹² below, or alternatively denotes

-   -   A¹² denotes

-   -   -   preferably

-   -   -   in which        -   L¹² on each occurrence, independently of one another,            denotes halogen, CN, or alkyl, alkenyl, alkoxy or alkenyloxy            having up to 12 C atoms and in which one or more H atoms are            optionally replaced with halogen, preferably methyl, ethyl,            Cl or F, particularly preferably F,

    -   A²¹ denotes

-   -   A²² has the meanings given for A¹²    -   A³¹ has the meanings given for A¹¹,        -   or alternatively denotes

-   -   A³² has the meanings given for A¹².

-   n2 on each occurrence, identically or differently, is 0, 1 or 2, and

-   n3 is 1, 2 or 3, and

-   r is 0, 1, 2, 3 or 4.

Particular preference is given to dopants selected from the groupconsisting of the compounds of the following formulae:

in whichm is, on each occurrence, identically or differently, an integer from 1to 9 andn is, on each occurrence, identically or differently, an integer from 2to 9.

Particularly preferred compounds of formula A are compounds of formulaA-III.

Further preferred dopants are derivatives of the isosorbide, isomannitolor isoiditol of the following formula A-IV:

-   in which the group

-    is

-   preferably dianhydrosorbitol,    and chiral ethane diols, such as, for example, diphenylethanediol    (hydrobenzoin), in particular mesogenic hydrobenzoin derivatives of    the following formula A-V:

-   including the (S,S) enantiomers, which are not shown,-   in which

-   -   are each, independently of one another, 1,4-phenylene, which may        also be mono-, di- or trisubstituted by L, or 1,4-cyclohexylene,

-   L is H, F, Cl, CN or optionally halogenated alkyl, alkoxy,    alkylcarbonyl, alkoxycarbonyl or alkoxycarbonyloxy having 1-7 carbon    atoms,

-   c is 0 or 1,

-   X is CH₂ or —C(O)—,

-   Z⁰ is —COO—, —OCO—, —CH₂CH₂— or a single bond, and

-   R⁰ is alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl or    alkylcarbonyloxy having 1-12 carbon atoms.

Examples of compounds of formula IV are:

The compounds of the formula A-IV are described in WO 98/00428. Thecompounds of the formula A-V are described in GB-A-2,328,207.

Very particularly preferred dopants are chiral binaphthyl derivatives,as described in WO 02/94805, chiral binaphthol acetal derivatives, asdescribed in WO 02/34739, chiral TADDOL derivatives, as described in WO02/06265, and chiral dopants having at least one fluorinated bridginggroup and a terminal or central chiral group, as described in WO02/06196 and WO 02/06195.

Particular preference is given to chiral compounds of the formula A-VI

-   in which-   X¹, X², Y¹ and Y² are each, independently of one another, F, Cl, Br,    I, CN, SCN, SF₅, straight-chain or branched alkyl having from 1 to    25 carbon atoms, which is unsubstituted or monosubstituted or    polysubstituted by F, Cl, Br, I or CN and in which, in addition, one    or more non-adjacent CH₂ groups may each, independently of one    another, be replaced by —O—, —S—, —NH—, NR^(x)—, —CO—, —COO—, —OCO—,    —OCOO—, —S—CO—, —CO—S—, —CH═CH— or —C≡C— in such a way that O and/or    S atoms are not bonded directly to one another, a polymerisable    group or cycloalkyl or aryl having up to 20 carbon atoms, which may    optionally be monosubstituted or polysubstituted by halogen,    preferably F, or by a polymerisable group,-   x¹ and x² are each, independently of one another, 0, 1 or 2,-   y¹ and y² are each, independently of one another, 0, 1, 2, 3 or 4,-   B¹ and B² are each, independently of one another, an aromatic or    partially or fully saturated aliphatic six-membered ring in which    one or more CH groups may each be replaced by N and one or more    non-adjacent CH₂ groups may each be replaced by O or S,-   W¹ and W² are each, independently of one another,    —Z¹-A¹-(Z²-A²)_(m)-R, and one of the two is alternatively R¹ or A³,    but both are not simultaneously H, or

-    is

-   -   or

-   U¹ and U² are each, independently of one another, CH₂, O, S, CO or    CS,-   V¹ and V² are each, independently of one another, (CH₂)_(n), in    which from one to four non-adjacent CH₂ groups may each be replaced    by O or S, and one of V¹ and V² and, in the case where

-    is

-   -   both are a single bond,

-   n is 1, 2 or 3

-   Z¹ and Z² are each, independently of one another, —O—, —S—, —CO—,    —COO—, —OCO—, —O—COO—, —CO—NR^(x)—, —NR^(x)—CO—, —O—CH₂—, —CH₂—O—,    —S—CH₂—, —CH₂—S—, —CF₂—O—, —O—CF₂—, —CF₂—S—, —S—CF₂—, —CH₂—CH₂—,    —CF₂—CH₂—, —CH₂—CF₂—, —CF₂—CF₂—, —CH═N—, —N═CH—, —N═N—, —CH═CH—,    —CF═CH—, —CH═CF—, —CF═CF—, —C═C—, a combination of two of these    groups, where no two O and/or S and/or N atoms are bonded directly    to one another, preferably —CH═CH—COO—, or —COO—CH═CH—, or a single    bond,

-   R^(x) denotes alkyl having 1 to 6 C atoms,

-   A¹, A² and A³ are each, independently of one another, 1,4-phenylene,    in which one or two non-adjacent CH groups may each be replaced by    N, 1,4-cyclohexylene, in which one or two non-adjacent CH₂ groups    may each be replaced by O or S, 1,3-dioxolane-4,5-diyl,    1,4-cyclohexenylene, 1,4-bicyclo[2.2.2]octylene,    piperidine-1,4-diyl, naphthalene-2,6-diyl,    decahydronaphthalene-2,6-diyl or    1,2,3,4-tetrahydronaphthalene-2,6-diyl, where each of these groups    may be monosubstituted or polysubstituted by L, and in addition A¹    can be a single bond,

-   L is a halogen atom, preferably F, CN, NO₂, alkyl, alkoxy,    alkylcarbonyl, alkoxycarbonyl or alkoxycarbonyloxy having 1-7 carbon    atoms, in which one or more H atoms may each be replaced by F or Cl,

-   m is in each case, independently, 0, 1, 2 or 3, and

-   R and R¹ are each, independently of one another, H, F, Cl, Br, I,    CN, SCN, SF₅, straight-chain or branched alkyl having from 1 or 3 to    25 carbon atoms respectively, which may optionally be    monosubstituted or polysubstituted by F, Cl, Br, I or CN, and in    which one or more non-adjacent CH₂ groups may each be replaced by    —O—, —S—, —NH—, —NR⁰—, —CO—, —COO—, —OCO—, —O—COO—, —S—CO—, —CO—S—,    —CH═CH— or —C≡C—, where no two O and/or S atoms are bonded directly    to one another, or a polymerisable group.

Particular preference is given to chiral binaphthyl derivatives of theformula A-VI-1

in which ring B, R⁰ and Z⁰ are as defined for the formulae A-IV and A-V,and b is 0, 1, or 2,in particular those selected from the following formulae A-VI-1a toA-VI-1c:

in which ring B, R⁰ and Z⁰ are as defined for the formula A-VI-1, and

-   R⁰ as defined for formula A-IV or H or alkyl having from 1 to 4    carbon atoms, and-   b is 0, 1 or 2,-   and Z⁰ is, in particular, —OC(O)— or a single bond.

The concentration of the one or more chiral dopant(s), in the LC mediumis preferably in the range from 0.001% to 20%, preferably from 0.05% to5%, more preferably from 0.1% to 2%, and, most preferably from 0.5% to1.5%. These preferred concentration ranges apply in particular to thechiral dopant S-4011 or R-4011 (both from Merck KGaA) and for chiraldopants having the same or a similar HTP. For Chiral dopants havingeither a higher or a lower absolute value of the HTP compared to S-4011these preferred concentrations have to be decreased, respectivelyincreased proportionally according to the ratio of their HTP valuesrelatively to that of S-4011.

The pitch p of the LC media or host mixtures according to the inventionis preferably in the range of from 5 to 50 μm, more preferably from 8 to30 m and particularly preferably from 10 to 20 μm.

Preferably, the media according to the invention, comprise a stabiliserselected from the group of compounds of the formulae ST-1 to ST-18.

-   in which-   R^(ST) denotes H, an alkyl or alkoxy radical having 1 to 15 C atoms,    where, in addition, one or more CH₂ groups in these radicals may    each be replaced, independently of one another, by —C≡C—, —CF₂O—,    —OCF₂—, —CH═CH—,

-    —O—, —CO—O—, —O—CO— in such a way that O atoms are not linked    directly to one another, and in which, in addition, one or more H    atoms may be replaced by halogen,

-    denotes

-   Z^(ST) each, independently of one another, denote —CO—O—, —O—CO—,    —CF₂O—, —OCF₂—, —CH₂O—, —OCH₂—, —CH₂—, —CH₂CH₂—, —(CH₂)₄—,    —CH═CH—CH₂O—, —C₂F₄—, —CH₂CF₂—, —CF₂CH₂—, —CF═CF—, —CH═CF—, —CF═CH—,    —CH═CH—, —C≡C— or a single bond,-   L¹ and L² each, independently of one another, denote F, Cl, CF₃ or    CHF₂,-   p denotes 1 or 2,-   q denotes 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

Of the compounds of the formula ST, special preference is given to thecompounds of the formulae

in which n=1, 2, 3, 4, 5, 6 or 7, preferably n=1 or 7

in which n=1, 2, 3, 4, 5, 6 or 7, preferably n=3

in which n=1, 2, 3, 4, 5, 6 or 7, preferably n=3

In the compounds of the formulae ST-3a and ST-3b, n preferably denotes3. In the compounds of the formula ST-2a, n preferably denotes 7.

Very particularly preferred mixtures according to the invention compriseone or more stabilisers from the group of the compounds of the formulaeST-2a-1, ST-3a-1, ST-3b-1, ST-8-1, ST-9-1 and ST-12:

The compounds of the formulae ST-1 to ST-18 are preferably each presentin the liquid-crystal mixtures according to the invention in amounts of0.005-0.5%, based on the mixture.

If the mixtures according to the invention comprise two or morecompounds from the group of the compounds of the formulae ST-1 to ST-18,the concentration correspondingly increases to 0.01-1% in the case oftwo compounds, based on the mixtures.

However, the total proportion of the compounds of the formulae ST-1 toST-18, based on the mixture according to the invention, should notexceed 2%.

The compounds according to the present invention can be synthesized byor in analogy to known methods described in the literature (for examplein the standard works such as Houben-Weyl, Methoden der OrganischenChemie [Methods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart),under reaction conditions which are known and suitable for saidreactions. Use may also be made here of variants which are known per se,but are not mentioned here. In particular, they can be prepared asdescribed in or in analogy to the following reaction schemes. Furthermethods for preparing the inventive compounds can be taken from theexamples.

Other mesogenic compounds which are not explicitly mentioned above canoptionally and advantageously also be used in the media in accordancewith the present invention. Such compounds are known to the personskilled in the art.

In a preferred embodiment of the present invention, the totalconcentration of compounds of formula U in the liquid-crystalline mediumis 5% or more, preferably 8% or more, very preferably 10% or more andparticularly preferably 12% or more.

In a preferred embodiment of the present invention, theliquid-crystalline media comprise in total 5% to 40%, preferably 10% to35% and particularly preferably 15% to 30% of compounds of formula U.

In a preferred embodiment of the present invention, theliquid-crystalline media comprise in total 10% to 45%, preferably 15% to40% and particularly preferably 20% to 35% of compounds of formula T,preferably selected from the formulae T-1a and T-2a, very preferablyfrom T-1a-5 and T-2a-4.

In a preferred embodiment of the present invention, theliquid-crystalline media comprise in total 5% to 35%, preferably 10% to30% and particularly preferably 15% to 25% of compounds of formulaeT-1a.

In a preferred embodiment, the medium comprises one or more compounds offormula I, preferably of formula I-2 in a total concentration in therange of from 1% to 25%, more preferably from 2% to 20%, andparticularly preferably from 5% to 15%.

In a preferred embodiment, the medium comprises one or more compounds offormula I-3 in a total concentration in the range of from 1% to 20%,more preferably from 2% to 15%, and particularly preferably from 3% to10%.

In a preferred embodiment of the present invention the medium comprisesone or more compounds of formula II, preferably of formula II-1, in atotal concentration of 5% to 35%, more preferably 10% to 30%,particularly preferably 15% to 25%.

In a preferred embodiment of the present invention the medium comprisesone or more compounds of formula IIA-1 in a total concentration of 5% to25%, more preferably 8% to 20%, particularly preferably 10% to 15%.

In a preferred embodiment of the present invention the medium comprisesone or more compounds of formula II-1 in an total concentration of 30%or less, more preferably 25% or less, particularly preferably 20% orless.

In a preferred embodiment of the present invention the medium comprisesone or more compounds of formula III, preferably III-1 and/or III-2,more preferably III-1h and/or III-1b, in a total concentration of 15% to70%, more preferably 25% to 60%, particularly preferably 35% to 50%.

Further preferred embodiments of the present invention, taken alone orin combination with one another, are as follows, wherein some compoundsare abbreviated using the acronyms given in Table C below:

-   -   The medium comprises one, two, three, four or more compounds of        formula III-1, preferably selected from the compounds of the        formulae III-1b, III-1f and III-1h; more preferably of III-1b        and III-1 h;    -   The medium comprises a compound of formula III-1b, preferably in        a total concentration in the range of from 2% to 30%, more        preferably 5% to 25%, in particular 10% to 20%;    -   The medium comprises a compound of formula III-1 h, preferably        in a total concentration in the range of from 10% to 40%, more        preferably 15% to 35%, in particular 20% to 30%;    -   The medium comprises the compound PPU-TO-S and/or PPTU-TO-S        and/or PTPU-TO-S and/or PP(1)TO-n-S;    -   The medium comprises one or more compounds of formula U and one        or more compounds of formula II-1 and/or one or more compounds        of the formula IIA-1, preferably in a total concentration in the        range of from 25% to 45%, in particular of 30% to 40%;    -   The medium comprises one or more compounds of formula I-2d,        preferably the compounds PGU-2-S and/or PGU-3-S and/or PGU-4-S;    -   The medium comprises one or more compounds of formula I-2d and        formula I-1b, preferably the compounds PGU-3-S and/or PGU-4-S        and PTU-3-S and/or PTU-4-S and/or PTU-5-S;    -   The medium comprises one or more compounds of formula PPTU-n-S        and/or PTPU-n-S in an total concentration in the range of from        10 to 20%;    -   The medium comprises one or more compounds of formula PPTU-n-S        and/or PTPU-n-S and/or PGTU-n-S in a total concentration in the        range of from 15 to 30%;    -   The medium comprises one or more compounds of formula ST-3,        preferably ST-3a and/or ST-3b, particularly preferably ST-3b-1,        in a total concentration in the range of from 0.01 to 1%,        preferably from 0.05 to 0.5%, particularly from 0.10 to 0.15%.

The liquid-crystal media in accordance with the present inventionpreferably have a clearing point of 90° C. or more, more preferably 100°C. or more, more preferably 110° C. or more, more preferably 120° C. ormore, more preferably 130° C. or more, particularly preferably 140° C.or more and very particularly preferably 150° C. or more.

The liquid-crystal media in accordance with the present inventionpreferably have a clearing point of 160° C. or less, more preferably140° C. or less, particularly preferably 120° C. or less, and veryparticularly preferably 100° C. or less.

The nematic phase of the media according to the invention preferablyextends at least from 0° C. or less to 90° C. or more. It isadvantageous for the media according to the invention to exhibit evenbroader nematic phase ranges, preferably at least from −10° C. or lessto 120° C. or more, very preferably at least from −20° C. or less to140° C. or more and in particular at least from −30° C. or less to 150°C. or more, very particularly preferably at least from −40° C. or lessto 170° C. or more.

The Δ≥ of the liquid-crystal medium according to the present invention,at 1 kHz and 20° C., is preferably 1 or more, more preferably 2 or moreand very preferably 3 or more.

The birefringence (Δn) of the liquid-crystal media according to thepresent invention, at 589 nm (Na^(D)) and 20° C., is preferably 0.280 ormore, more preferably 0.300 or more, even more preferably 0.320 or more,very preferably 0.330 or more and in particular 0.350 or more.

The Δn of the liquid-crystal media according to the present invention,at 589 nm (Na^(D)) and 20° C., is preferably in the range from 0.200 to0.900, more preferably in the range from 0.250 to 0.800, even morepreferably in the range from 0.300 to 0.700 and very particularlypreferably in the range from 0.350 to 0.600.

In a preferred embodiment of the present application, the Δn of theliquid-crystal media in accordance with the present invention ispreferably 0.50 or more, more preferably 0.55 or more.

The compounds of the formulae I to III in each case includedielectrically positive compounds having a dielectric anisotropy ofgreater than 3, dielectrically neutral compounds having a dielectricanisotropy of less than 3 and greater than −1.5 and dielectricallynegative compounds having a dielectric anisotropy of −1.5 or less.

The compounds of the formulae U, I, II and III are preferablydielectrically positive.

-   V_(o) denotes threshold voltage, capacitive, [V] at 20° C., in an    antiparallel rubbed cell,-   n_(e) denotes extraordinary refractive index at 20° C. and 589 nm,-   n_(o) denotes ordinary refractive index at 20° C. and 589 nm,-   Δn denotes optical anisotropy at 20° C. and 589 nm,-   ε_(⊥) denotes dielectric permittivity perpendicular to the director    at 20° C. and 1 kHz,-   ε_(∥) denotes dielectric permittivity parallel to the director at    20° C. and 1 kHz,-   Δε denotes dielectric anisotropy (Δε=ε_(∥)−ε_(⊥)) at 20° C. and 1    kHz,-   T(N,I) denotes clearing point [° C.], i.e. nematic to isotropic    phase transition,-   γ₁ denotes rotational viscosity measured at 20° C. [mPa·s],-   K₁ denotes elastic constant, “splay” deformation at 20° C. [pN],-   K₂ denotes elastic constant, “twist” deformation at 20° C. [pN],-   K₃ denotes elastic constant, “bend” deformation at 20° C. [pN],

In the present application, the expression dielectrically positivedescribes compounds or components where Δε>3.0, dielectrically neutraldescribes those where −1.5≤Δε≤3.0 and dielectrically negative describesthose where Δε<−1.5. Δε is determined at a frequency of 1 kHz and at 20°C. The dielectric anisotropy of the respective compound is determinedfrom the results of a solution of 10% of the respective individualcompound in a nematic host mixture. If the solubility of the respectivecompound in the host mixture is less than 10%, the concentration isreduced to 5%. The capacitances of the test mixtures are determined bothin a cell having homeotropic alignment and in a cell having homogeneousalignment. The cell thickness of both types of cells is approximately 20μm. The voltage applied is a rectangular wave having a frequency of 1kHz and an effective value of typically 0.5 V to 1.0 V, but it is alwaysselected to be below the capacitive threshold of the respective testmixture.

Δε is defined as (ε_(∥)−ε_(⊥)), while ε_(ave.) is (ε_(∥)+2 ε_(⊥))/3.

The host mixture used for the determination of physical constants ofpure compounds by extrapolation is ZLI-4792 from Merck KGaA, Germany.The absolute values of the dielectric constants, the birefringence (Δn)and the rotational viscosity (γ₁) of the compounds are determined fromthe change in the respective values of the host mixture on addition ofthe compounds. The concentration in the host is 10% or in case ofinsufficient solubility 5%. The values are extrapolated to aconcentration of 100% of the added compounds.

In the examples, the phase sequences of pure compounds are given usingthe following abbreviations:

K: crystalline, N: nematic, SmA: smectic A, SmB: smectic B, I:isotropic.

Components having a nematic phase at the measurement temperature of 20°C. are measured as such, all others are treated like compounds.

The expression threshold voltage in the present application refers tothe optical threshold and is quoted for 10% relative contrast (V₁₀), andthe expression saturation voltage refers to the optical saturation andis quoted for 90% relative contrast (V₉₀), in both cases unlessexpressly stated otherwise. The capacitive threshold voltage (V₀), alsocalled the Freedericks threshold (V_(Fr)), is only used if expresslymentioned.

The parameter ranges indicated in this application all include the limitvalues, unless expressly stated otherwise.

The different upper and lower limit values indicated for various rangesof properties in combination with one another give rise to additionalpreferred ranges.

Throughout this application, the following conditions and definitionsapply, unless expressly stated otherwise. All concentrations are quotedin percent by weight and relate to the respective mixture as a whole,all temperatures are quoted in degrees Celsius and all temperaturedifferences are quoted in differential degrees. All physical propertiesare determined in accordance with “Merck Liquid Crystals, PhysicalProperties of Liquid Crystals”, Status November 1997, Merck KGaA,Germany, and are quoted for a temperature of 20° C., unless expresslystated otherwise. The optical anisotropy (Δn) is determined at awavelength of 589.3 nm. The dielectric anisotropy (Δε) is determined ata frequency of 1 kHz. The threshold voltages, as well as all otherelectro-optical properties, are determined using test cells produced atMerck KGaA, Germany. The test cells for the determination of Δε have acell thickness of approximately 20 μm. The electrode is a circular ITOelectrode having an area of 1.13 cm² and a guard ring. The orientationlayers are SE-1211 from Nissan Chemicals, Japan, for homeotropicorientation (ε_(∥)) and polyimide AL-1054 from Japan Synthetic Rubber,Japan, for homogeneous orientation (ε_(⊥)). The capacitances aredetermined using a Solatron 1260 frequency response analyser using asine wave with a voltage of 0.3 Vrms. The light used in theelectro-optical measurements is white light. A set-up using acommercially available DMS instrument from Autronic-Melchers, Germany,is used here. The characteristic voltages have been determined underperpendicular observation. The threshold (V₁₀), mid-grey (V₅₀) andsaturation (V₉₀) voltages have been determined for 10%, 50% and 90%relative contrast, respectively.

The liquid-crystalline media are investigated with respect to theirproperties in the microwave frequency range as described in A.Penirschke et al. “Cavity Perturbation Method for Characterization ofLiquid Crystals up to 35 GHz”, 34^(th) European MicrowaveConference—Amsterdam, pp. 545-548. Compare in this respect also A.Gaebler et al. “Direct Simulation of Material Permittivities . . . ”,12MTC 2009—International Instrumentation and Measurement TechnologyConference, Singapore, 2009 (IEEE), pp. 463-467, and DE 10 2004 029 429A, in which a measurement method is likewise described in detail.

The liquid crystal is introduced into a polytetrafluoroethylene (PTFE)or quartz capillary. The capillary has an inner diameter of 0.5 mm andan outer diameter of 0.78 mm. The effective length is 2.0 cm. The filledcapillary is introduced into the centre of the cylindrical cavity with aresonance frequency of 19 GHz. This cavity has a length of 11.5 mm and aradius of 6 mm. The input signal (source) is then applied, and thefrequency depending response of the cavity is recorded using acommercial vector network analyser (N5227A PNA Microwave NetworkAnalyzer, Keysight Technologies Inc. USA. For other frequencies, thedimensions of the cavity are adapted correspondingly.

The change in the resonance frequency and the Q factor between themeasurement with the capillary filled with the liquid crystal and themeasurement without the capillary filled with the liquid crystal is usedto determine the dielectric constant and the loss angle at thecorresponding target frequency by means of equations 10 and 11 in theabove-mentioned publication A. Penirschke et al., 34^(th) EuropeanMicrowave Conference—Amsterdam, pp. 545-548, as described therein.

The values for the components of the properties perpendicular andparallel to the director of the liquid crystal are obtained by alignmentof the liquid crystal in a magnetic field. To this end, the magneticfield of a permanent magnet is used. The strength of the magnetic fieldis 0.35 tesla.

Preferred components are phase shifters, varactors, wireless and radiowave antenna arrays, matching circuit adaptive filters and others.

In the present application, the term compounds is taken to mean both onecompound and a plurality of compounds, unless expressly statedotherwise.

All mixtures according to the invention are nematic. The liquid-crystalmedia according to the invention preferably have nematic phases inpreferred ranges given above. The expression have a nematic phase heremeans on the one hand that no smectic phase and no crystallisation areobserved at low temperatures at the corresponding temperature and on theother hand that no clearing occurs on heating from the nematic phase. Athigh temperatures, the clearing point is measured in capillaries byconventional methods. The investigation at low temperatures is carriedout in a flow viscometer at the corresponding temperature and checked bystorage of bulk samples: The storage stability in the bulk (LTS) of themedia according to the invention at a given temperature T is determinedby visual inspection. 2 g of the media of interest are filled into aclosed glass vessel (bottle) of appropriate size placed in arefrigerator at a predetermined temperature. The bottles are checked atdefined time intervals for the occurrence of smectic phases orcrystallisation. For every material and at each temperature two bottlesare stored. If crystallisation or the appearance of a smectic phase isobserved in at least one of the two correspondent bottles the test isterminated and the time of the last inspection before the one at whichthe occurrence of a higher ordered phase is observed is recorded as therespective storage stability. The test is finally terminated after 1000h, i.e an LTS value of 1000 h means that the mixture is stable at thegiven temperature for at least 1000 h.

The liquid crystals employed preferably have a positive dielectricanisotropy. This is preferably 2 or more, preferably 4 or more,particularly preferably 6 or more and very particularly preferably 10 ormore.

Furthermore, the liquid-crystal media according to the invention arecharacterised by high anisotropy values in the microwave range. Thebirefringence at about 19 GHz is, for example, preferably 0.14 or more,particularly preferably 0.15 or more, particularly preferably 0.20 ormore, particularly preferably 0.25 or more and very particularlypreferably 0.30 or more. In addition, the birefringence is preferably0.80 or less.

The dielectric anisotropy in the microwave range is defined asΔε_(r)≡(ε_(r,∥)−ε_(r,⊥))

The tunability (τ) is defined asτ≡(Δε_(r)/ε_(r,∥)).

The material quality (η) is defined asη≡(τ/tan δ_(ε r,max.)), wherethe maximum dielectric loss istan δ_(ε r,max.)≡max.{tan δ_(ε r,⊥);tan δ_(ε r,∥)}.

The tunability τ of the medium according to the invention, measured at20° C. and 19 GHz is 0.250 or more, preferably 0.300 or more, 0.310 ormore, 0.320 or more, 0.330 or more, or 0.340 or more, very preferably0.345 or more and in particular 0.350 or more.

The material quality (η) of the preferred liquid-crystal materials is 6or more, preferably 8 or more, preferably 10 or more, preferably 15 ormore, preferably 17 or more, preferably 20 or more, particularlypreferably 25 or more and very particularly preferably 30 or more.

In the corresponding components, the preferred liquid-crystal materialshave phase shifter qualities of 15°/dB or more, preferably 20°/dB ormore, preferably 30°/dB or more, preferably 40°/dB or more, preferably50°/dB or more, particularly preferably 80°/dB or more and veryparticularly preferably 100°/dB or more.

In some embodiments, however, liquid crystals having a negative value ofthe dielectric anisotropy can also advantageously be used.

The liquid crystals employed are either individual substances ormixtures. They preferably have a nematic phase.

The liquid-crystal media in accordance with the present invention maycomprise further additives and chiral dopants in the usualconcentrations. The total concentration of these further constituents isin the range from 0% to 10%, preferably 0.1% to 6%, based on the mixtureas a whole. The concentrations of the individual compounds used are eachpreferably in the range from 0.1% to 3%. The concentration of these andsimilar additives is not taken into consideration when quoting thevalues and concentration ranges of the liquid-crystal components andliquid-crystal compounds of the liquid-crystal media in thisapplication.

Preferably the media according to the present invention comprise one ormore chiral compounds as chiral dopants in order to adjust theircholesteric pitch. Their total concentration in the media according tothe instant invention is preferably in the range 0.05% to 15%, morepreferably from 1% to 10% and most preferably from 2% to 6%.

Optionally the media according to the present invention may comprisefurther liquid crystal compounds in order to adjust the physicalproperties. Such compounds are known to the expert. Their concentrationin the media according to the instant invention is preferably 0% to 30%,more preferably 0.1% to 20% and most preferably 1% to 15%.

The response times are given as rise time (τ_(on)) for the time for thechange of the relative tuning, respectively of the relative contrast forthe electro-optical response, from 0% to 90% (t₉₀−t₀), i.e. includingthe delay time (t₁₀−t₀), as decay time (τ_(off)) for the time for thechange of the relative tuning, respectively of the relative contrast forthe electro-optical response, from 100% back to 10% (t₁₀₀−t₁₀) and asthe total response time (τ_(total)=τ_(on)+τ_(on)), respectively.

The liquid-crystal media according to the invention consist of aplurality of compounds, preferably 3 to 30, more preferably 4 to 20 andvery preferably 4 to 16 compounds. These compounds are mixed in aconventional manner. In general, the desired amount of the compound usedin the smaller amount is dissolved in the compound used in the largeramount. If the temperature is above the clearing point of the compoundused in the higher concentration, it is particularly easy to observecompletion of the dissolution process. It is, however, also possible toprepare the media in other conventional ways, for example usingso-called pre-mixes, which can be, for example, homologous or eutecticmixtures of compounds, or using so-called “multibottle” systems, theconstituents of which are themselves ready-to-use mixtures.

All temperatures, such as, for example, the melting point T(C,N) orT(C,S), the transition from the smectic (S) to the nematic (N) phaseT(S,N) and the clearing point T(N,I) of the liquid crystals, are quotedin degrees Celsius. All temperature differences are quoted indifferential degrees.

In the present invention and especially in the following examples, thestructures of the mesogenic compounds are indicated by means ofabbreviations, also referred to as acronyms. In these acronyms, thechemical formulae are abbreviated as follows using Tables A to D below.All groups C_(n)H_(2n+1), C_(m)H_(2m+1) and C_(l)H_(2l+1) orC_(n)H_(2n−1), C_(m)H_(2m−1) and C_(l)H_(2l−1) denote straight-chainalkyl or alkenyl, preferably 1-E-alkenyl, respectively, in each casehaving n, m or l C atoms. Table A lists the codes used for the ringelements of the core structures of the compounds, while Table B showsthe linking groups. Table C gives the meanings of the codes for theleft-hand or right-hand end groups. Table D shows illustrativestructures of compounds with their respective abbreviations.

TABLE A Ring elements C

D

DI

A

AI

G

GI

U

UI

U(F,F)

Y

M

MI

N

NI

Np

N3f

N3fI

tH

tHI

tH2f

tH2fI

dH

K

KI

L

LI

F

FI

P

P(n,m)

P(o)

PI(o)

P(i3)

PI(ic3)

P(t4)

PI(t4)

P(c3)

PI(c3)

P(c4)

PI(c4)

P(c5)

PI(c5)

P(e5)

PI(e5)

P(c6)

PI(c6)

P(e6)

PI(e6)

GI(o)

G(o)

GI(i3)

G(i3)

GI(t4)

G(t4)

GI(c3)

G(c3)

GI(c4)

G(c4)

GI(c5)

G(c5)

GI(e5)

G(e5)

GI(c6)

G(c6)

GI(e6)

G(e6)

Np(1,4)

Th

TABLE B Linking groups E —CH₂CH₂— Z —CO—O— V —CH═CH— ZI —O—CO— X —CF═CH—O —CH₂—O— XI —CH═CF— OI —O—CH₂— B —CF═CF— Q —CF₂—o— T —C≡C— QI —O—CF₂— W—CF₂CF₂—

TABLE B End groups Left-hand side Right-hand side Used alone -n-C_(n)H_(2n+1—) -n -C_(n)H_(2n+1) -nO— C_(n)H_(2n+1)—O— —On—O—C_(n)H_(2n+1) —V— CH₂═CH— —V —CH═CH₂ -nV— C_(n)H_(2n+1)—CH═CH— -nV—C_(n)H_(2n)—CH═CH₂ —Vn- CH₂═CH—C_(n)H_(2n+1)— —Vn —CH═CH—C_(n)H_(2n+1)-nVm- C_(n)H_(2n+1)—CH═CH—C_(m)H_(2m)— -nVm—C_(n)H_(2n)—CH═CH—C_(m)H_(2m+1) —N— N≡C— —N —C≡N —S— S═C═N— —S —N═C═S—F— F— —F —F —CL— Cl— —CL —Cl —M— CFH₂— —M —CFH₂ —D— CF₂H— —D —CF₂H —T—CF₃— —T —CF₃ —MO— CFH₂O— —OM —OCFH₂ —DO— CF₂HO— —OD —OCF₂H —TO— CF₃O——OT —OCF₃ —FXO— CF₂═CH—O— —OXF —O—CH═CF₂ —A— H—C≡C— —A —C≡C—H —nA—C_(n)H_(2n+1)—C≡C— —An —C≡C—C_(n)H_(2n+1) —NA— N≡C—C≡C— —AN —C≡C—C≡N-(cn)-

-(cn)

-(cn)m-

-m(cn)

Used in Combination with Others

—...A...— —C≡C— —...A... —C≡C— —...V...— —CH═CH— —...V... —CH═CH——...Z...— —CO—O— —...Z... —CO—O— —...ZI...— —O—CO— —...ZI... —O—CO——...K...— —CO— —...K... —CO— —...W...— —CF═CF— —...W... —CF═CF—in which n and m each denote integers, and the three dots “ . . . ” areplaceholders for other abbreviations from this table.

Branched lateral groups are numbered starting from the position next tothe ring (1) where the longest chain is selected, the smaller numberindicating the length of the branch and the superscript number inbrackets indicates the position of the branch, for example:

The following table shows illustrative structures together with theirrespective abbreviations. These are shown in order to illustrate themeaning of the rules for the abbreviations. They furthermore representcompounds which are preferably used.

TABLE C Illustrative structures

The following illustrative structures are compounds, which arepreferably additionally used in the media:

in which m and n, identically or differently, are 1, 2, 3, 4, 5, 6 or 7.

Preferably, the medium according to the invention comprises one or morecompounds selected from the compounds of Table C.

The following table, Table D, shows illustrative compounds which can beused as alternative stabilisers in the mesogenic media in accordancewith the present invention. The total concentration of these and similarcompounds in the media is preferably 5% or less.

TABLE D

In a preferred embodiment of the present invention, the mesogenic mediacomprise one or more compounds selected from the group of the compoundsfrom Table D. The following table, Table E, shows illustrative compoundswhich can preferably be used as chiral dopants in the mesogenic media inaccordance with the present invention.

TABLE E

  C 15

  CB 15

  CM 21

  CM 44

  CM 45

  CM 47

  CC

  CN

  R/S-811

  R/S-1011

  R/S-2011

  R/S-3011

  R/S-4011

  R/S-5011

In a preferred embodiment of the present invention, the mesogenic mediacomprise one or more compounds selected from the group of the compoundsof Table E.

The mesogenic media in accordance with the present applicationpreferably comprise two or more, preferably four or more, compoundsselected from the group consisting of the compounds from the abovetables.

EXAMPLES

The following examples illustrate the present invention without limitingit in any way. It is clear to the person skilled in the art from thephysical properties what properties can be achieved and in what rangesthey can be modified. In particular, the combination of the variousproperties which can preferably be achieved is thus well defined for theperson skilled in the art.

Synthesis Examples

Abbreviations:

RT room temperature (typically 20° C.±1° C.)

THE Tetrahydrofuran

MTB ether Methyl-tert-butyl ether

DCM Dichloromethane

dist. distilled

Example 1:1,2,4,5-Tetrafluoro-3-isothiocyanato-6-[4-(4-propylcyclohexyl)phenyl]benzeneStep 1.1: 2,3,5,6-Tetrafluoro-4-[4-(4-propylcyclohexyl)phenyl]aniline

A solution of [4-(4-propylcyclohexyl)phenyl]boronic acid (CAS-no.156837-90-0, 5.3 g, 22 mmol) and 4-bromo-2,3,5,6-tetrafluoro-aniline(CAS-no. 1998-66-9, 5.0 g, 21 mmol) in THE (30 mL) is heated to 50° C.,andbis(di-tert-butyl(4-dimethylaminophenyl)phosphine)dichloropalladium(II)(0.87 mg) is added. The mixture is heated to reflux temperature,followed by dropwise addition of sodium hydroxide solution (2 M, 15.4mL, 31 mmol). The reaction mixture is stirred for 2 h at refluxtemperature, then again a solution of[4-(4-propylcyclohexyl)phenyl]boronic acid (1.0 g, 4 mmol) in THE (15mL) is added dropwise, and the mixture is stirred at reflux temperatureovernight. It is then cooled to RT, treated with acetic acid (glacial,1.6 mL) and diluted with MTB ether. The aqueous phase is separated andextracted with MTB ether. The combined organic phases are washed withbrine, dried (sodium sulfate) and concentrated in vacuo. The residue ispurified by silica gel chromatography (n-heptane and MTB ether) to give2,3,5,6-tetrafluoro-4-[4-(4-propylcyclohexyl)phenyl]aniline as a lightyellow solid.

Step 1.2:1,2,4,5-Tetrafluoro-3-isothiocyanato-6-[4-(4-propylcyclohexyl)phenyl]benzene

A solution of2,3,5,6-tetrafluoro-4-[4-(4-propylcyclohexyl)phenyl]aniline (7.4 g, 20mmol) and 1,4-diazabicyclo[2.2.2]octane (5.7 g, 51 mmol) in DCM (100 mL)is cooled to 0° C., and thiophosgene (1.8 mL, 22 mmol) is addeddropwise. The reaction mixture is stirred at RT for 60 min. Then thereaction mixture is hydrolyzed with dist. water and brine and dilutedwith DCM. The aqueous phase is separated and extracted with DCM. Thecombined organic phases are washed with brine, dried (sodium sulfate)and concentrated in vacuo. The residue is purified by silica gelchromatography (n-heptane) and crystallization (n-heptane).1,2,4,5-tetrafluoro-3-isothiocyanato-6-[4-(4-propylcyclohexyl)phenyl]benzeneis isolated as a colorless solid.

Phase sequence K 64 N 174.4 I.

Δε=6.80

Δn=0.2522

γ₁=472 m Pas

Example 2:1,2,4,5-Tetrafluoro-3-isothiocyanato-6-[4-[4-(trifluoromethoxy)phenyl]phenyl]benzeneStep 2.1:4,4,5,5-Tetramethyl-2-[4-[4-(trifluoromethoxy)phenyl]phenyl]-1,3,2-dioxaborolane

Bis-(pinacolato)-diboron (14.3 g, 56 mmol) and potassium acetate (14.3g, 146 mmol) are added to a solution of1-bromo-4-[4-(trifluoromethoxy)phenyl]benzene (CAS-no. 134150-03-1, 16.9g, 49 mmol) in 1,4-dioxane (150 mL). Then the mixture is treated with1,1′-bis(biphenylphosphine)ferrocene-palladium dichloride (1.2 g, 1.6mmol) and stirred at reflux temperature overnight. The reaction mixtureis cooled to RT, hydrolyzed with dist. water, diluted with MTB ether andfiltered over celite. The aqueous phase is separated and extracted withMTB ether. The combined organic phases are washed with brine, dried(sodium sulfate) and concentrated in vacuo. The residue is purified bysilica gel chromatography (n-heptane and 1-chlorobutane) to give4,4,5,5-tetramethyl-2-[4-[4-(trifluoromethoxy)phenyl]phenyl]-1,3,2-dioxaborolaneas a brown solid.

Step 2.2:2,3,5,6-Tetrafluoro-4-[4-[4-(trifluoromethoxy)phenyl]phenyl]aniline

A solution of4,4,5,5-tetramethyl-2-[4-[4-(trifluoromethoxy)phenyl]phenyl]-1,3,2-dioxaborolane(3.0 g, 7.4 mmol) and 4-bromo-2,3,5,6-tetrafluoro-aniline (1.6 g, 6.6mmol) in THE (11 mL) is treated withbis(di-tert-butyl-(4-dimethylaminophenyl)-phosphine)dichloropalladium(II)(0.31 mg) at 50° C. Then the mixture is heated to reflux temperature,followed by dropwise addition of sodium hydroxide solution (2.0 M, 5.5mL). The reaction mixture is stirred at reflux temperature overnight.Then it is cooled to RT, treated with acetic acid (glacial, 0.6 mL) anddiluted with MTB ether. The aqueous phase is separated and extractedwith MTB ether. The combined organic phases are washed with brine, dried(sodium sulfate) and concentrated in vacuo. The residue is purified bysilica gel chromatography (n-heptane and 1-chlorobutane).2,3,5,6-Tetrafluoro-4-[4-[4-(trifluoromethoxy)phenyl]phenyl]aniline isisolated as a light brown solid.

Step 2.3:1,2,4,5-Tetrafluoro-3-isothiocyanato-6-[4-[4-(trifluoromethoxy)phenyl]phenyl]benzene

A solution of2,3,5,6-tetrafluoro-4-[4-[4-(trifluoromethoxy)phenyl]phenyl]aniline (2.0g, 4.9 mmol) and 1,4-diazabicyclo[2.2.2]octane (1.4 g, 12.2 mmol) in DCM(25 mL) is cooled to 0° C. and treated dropwise with thiophosgene (0.4mL, 5.4 mmol). The reaction mixture is stirred at RT for 60 min. Then itis hydrolyzed with dist. water and brine and diluted with DCM. Theaqueous phase is separated and extracted with DCM. The combined organicphases are washed with brine, dried (sodium sulfate) and concentrated invacuo. The residue is purified by silica gel chromatography (n-heptaneand 1-chlorobutane) and crystallization (n-heptane) to give1,2,4,5-tetrafluoro-3-isothiocyanato-6-[4-[4-(trifluoromethoxy)phenyl]phenyl]benzeneas a colorless solid. Phase sequence: K 109 N 154.5 I.

Δε=1.79

Δn=0.2984

γ₁=458 m Pas

Example 3:1-[4-[2-(4-Butylphenyl)ethynyl]phenyl]-2,3,5,6-tetrafluoro-4-isothiocyanato-benzeneStep 3.1:2-[4-[2-(4-Butylphenyl)ethynyl]phenyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

A solution of 1-butyl-4-ethynyl-benzene (CAS-no. 79887-09-5, 1.2 g, 7.1mmol), 2-(4-bromophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane(CAS-no. 68716-49-4, 2.0 g, 7.1 mmol) and diisopropylamine (17 mL) inTHE (20 mL) is heated slightly below reflux temperature. Copper(I)iodide(1.4 mg), 2-dicyclohexylphosphino-2′4′6′-triisopropyl-1,1′-biphenyl (6.7mg) andchloro(2-dicyclohexylphosphino-2′4′6′-triisopropyl-1,1′-biphenyl)(2′-amino-1,1′-biphenyl-2-yl)palladium(II)(11.1 mg) are added, and the reaction mixture is stirred at refluxtemperature overnight. Then it is cooled down to RT, filtered andconcentrated in vacuo. The residue is purified by silica gelchromatography (n-heptane and 1-chlorobutane) to give2-[4-[2-(4-butylphenyl)ethynyl]phenyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolaneas a brown oil, which crystallizes on standing.

Step 3.2:4-[4-[2-(4-Butylphenyl)ethynyl]phenyl]-2,3,5,6-tetrafluoro-aniline

A solution of2-[4-[2-(4-butylphenyl)ethynyl]phenyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane(1.8 g, 4.7 mmol) and 4-bromo-2,3,5,6-tetrafluoro-aniline (1.2 g, 4.7mmol) in THE (10 mL) is treated withbis(di-tert-butyl(4-dimethylaminophenyl)phosphine)dichloropalladium(II)(0.2 mg) at 50° C. Then the reaction mixture is heated to refluxtemperature, followed by dropwise addition of sodium hydroxide solution(2.0 M, 3.6 mL) and the reaction is stirred at reflux temperatureovernight. Then the reaction mixture is cooled to RT, treated withacetic acid (glacial, 0.4 mL) and diluted with MTB ether. The aqueousphase is separated and extracted with MTB ether. The combined organicphases are washed with brine, dried (sodium sulfate) and concentrated invacuo. The residue is purified by silica gel chromatography (n-heptaneand 1-chlorobutane) to give4-[4-[2-(4-butylphenyl)ethynyl]phenyl]-2,3,5,6-tetrafluoro-aniline as alight yellow solid.

Step 3.3:1-[4-[2-(4-Butylphenyl)ethynyl]phenyl]-2,3,5,6-tetrafluoro-4-isothiocyanato-benzene

A solution of4-[4-[2-(4-butylphenyl)ethynyl]phenyl]-2,3,5,6-tetrafluoro-aniline (3.0g, 6.8 mmol) and 1,4-diazabicyclo[2.2.2]octane (1.9 g, 7.4 mmol) in DCM(35 mL) is treated dropwise with thiophosgene (0.6 mL, 7.4 mmol) at 0°C. Then the reaction mixture is stirred at RT for 60 min. It ishydrolyzed with dist. water and brine and diluted with DCM. The aqueousphase is separated and extracted with DCM. The combined organic phasesare washed with brine, dried (sodium sulfate) and concentrated in vacuo.The residue is purified by silica gel chromatography (n-heptane and MTBether) and crystallization (acetone) to give1-[4-[2-(4-butylphenyl)ethynyl]phenyl]-2,3,5,6-tetrafluoro-4-isothiocyanato-benzeneas a colorless solid.

Phase sequence K 127 SmA (120) N 192.3 I.

Δε=9.10

Δn=0.4190

γ₁=859 mPas

Example 4:1,2,4,5-Tetrafluoro-3-isothiocyanato-6-[4-[2-[4-(trifluoromethoxy)phenyl]ethynyl]phenyl]benzeneStep 4.1:4,4,5,5-Tetramethyl-2-[4-[2-[4-(trifluoromethoxy)phenyl]ethynyl]phenyl]-1,3,2-dioxaborolane

A solution of 1-ethynyl-4-(trifluoromethoxy)benzene (CAS-no.160542-02-9, 3.0 g, 15 mmol),2-(4-bromophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (4.3 g, 15mmol) and diisopropylamine (37 mL) in THE (40 mL) is heated slightlybelow reflux temperature. Copper(I)iodide (2.9 mg),2-dicyclohexylphosphino-2′4′6′-triisopropyl-1,1′-biphenyl (14.6 mg) andchloro(2-dicyclohexylphosphino-2′4′6′-triisopropyl-1,1′-biphenyl)(2′-amino-1,1′-biphenyl-2-yl)palladium(II)(24 mg) are added, and the reaction mixture is stirred at refluxtemperature overnight. It is then cooled to RT, filtered andconcentrated in vacuo. The residue is purified by silica gelchromatography (solvents n-heptane and DCM) to give4,4,5,5-tetramethyl-2-[4-[2-[4-(trifluoromethoxy)phenyl]-ethynyl]phenyl]-1,3,2-dioxaborolaneas a brown oil, which crystallizes on standing.

Step 4.2:2,3,5,6-Tetrafluoro-4-[4-[2-[4-(trifluoromethoxy)phenyl]ethynyl]phenyl]aniline

A solution of4,4,5,5-tetramethyl-2-[4-[2-[4-(trifluoromethoxy)phenyl]ethynyl]phenyl]-1,3,2-dioxaborolane(5.8 g, 12 mmol) and 4-bromo-2,3,5,6-tetrafluoro-aniline (2.9 g, 12mmol) in THE (18 mL) is treated withbis(di-tert-butyl(4-dimethylaminophenyl)phosphine)-dichloropalladium(II)(0.5 mg) at 50° C. Then the reaction mixture is heated to refluxtemperature, followed by dropwise addition of sodium hydroxide solution(2.0 M, 9.3 mL). It is stirred at reflux temperature overnight. Then thereaction mixture is cooled to RT, treated with acetic acid (glacial, 1.1mL) and diluted with MTB ether. The aqueous phase is separated andextracted with MTB ether. The combined organic phases are washed withbrine, dried (sodium sulfate) and concentrated in vacuo. The residue ispurified by silica gel chromatography (solvents n-heptane and1-chlorobutane) to give2,3,5,6-tetrafluoro-4-[4-[2-[4-(trifluoromethoxy)phenyl]ethynyl]phenyl]anilineas a light yellow solid.

Step 4.3:1,2,4,5-Tetrafluoro-3-isothiocyanato-6-[4-[2-[4-(trifluoromethoxy)phenyl]ethynyl]phenyl]benzene

A solution of2,3,5,6-tetrafluoro-4-[4-[2-[4-(trifluoromethoxy)phenyl]ethynyl]phenyl]aniline(4.7 g, 8 mmol) and 1,4-diazabicyclo[2.2.2]octane (2.2 g, 19 mmol) inDCM (30 mL) is treated dropwise with thiophosgene (0.6 mL, 7.8 mmol) at0° C. The reaction mixture is stirred at RT for 60 min. Then it ishydrolyzed with dist. water and brine and diluted with DCM. The aqueousphase is separated and extracted with DCM. The combined organic phasesare washed with brine, dried (sodium sulfate) and concentrated in vacuo.The residue is purified by silica gel chromatography (n-heptane and1-chlorobutane) and crystallization (n-heptane and acetone).1,2,4,5-tetrafluoro-3-isothiocyanato-6-[4-[2-[4-(trifluoromethoxy)phenyl]ethynyl]phenyl]benzeneis obtained as a colorless solid.

Phase sequence: K 126 N 190.9 I.

Δε=2.52

Δn=0.3769

γ₁=666 mPas

In analogy to Synthesis Examples 1 to 4 the following compounds areobtained:

physical No. Compound parameters  5

 6

K 51 I Δε = 5.50 Δn = 0.2152 γ₁ = 45 mPas  7

K 56 I Δε = 4.60 Δn = 0.2030 γ₁ = 45 mPas  8

 9

10

11

12

13

K 75 I Δε = 8.90 Δn = 0.3533 γ₁ = 46 mPas 14

15

16

17

18

K 146 N 170.5 I 19

20

21

22

K 88 N 169.3 I Δε = 6.30 Δn = 0.2354 γ₁ = 466 mPas 23

K 101 N 191.2 I Δε = 6.60 Δn = 0.2391 γ₁ = 466 mPas 24

K 74 N 162.3 I Δε = 6.40 Δn = 0.2948 γ₁ = 656 mPas 25

K 75 N 77.2 I Δε = 3.52 Δn = 0.1911 γ₁ = 1048 mPas 25

T_(g) −49 K 53 N 142.9 I Δε = 8.12 Δn = 0.2248 γ₁ = 600 mPas 26

27

28

K 72 N 137.1 I Δε = 8.63 Δn = 0.2443 γ₁ = 582 mPas 29

K 103 N 123.9 I Δε = 11.14 Δn = 0.2294 γ₁ = 598 mPas 30

31

K 123 N 240.6 I Δε = 9.90 Δn = 0.3730 γ₁ = 352 mPas 32

33

34

35

36

37

38

K 98 N 170.3 I Δε = 6.12 Δn = 0.2989 γ₁ = 1262 mPas 39

K 133 N 248.1 I 40

41

42

43

44

45

K 142 N 149.7 I 46

K 42 I Δε = 6.50 Δn = 0.1852 γ₁ = 43 mPas 47

48

49

50

51

52

MIXTURE EXAMPLES

Liquid-crystal mixtures N1 to N13 having the compositions and propertiesas indicated in the following tables are prepared and characterized withrespect to their general physical properties and their applicability inmicrowave components at 19 GHz and 20° C.

Comparative Mixture C1

PTU-3-S 10.0 T(N, I) [° C.]: 156 PTU-5-S 10.0 Δε [1 kHz, 20° C.]: 17.5PPTU-4-S 6.0 ε_(||) [1 kHz, 20° C.]: 21.5 PPTU-5-S 12.0 ε_(⊥) [1 kHz,20° C.]: 4.0 PGU-3-S 14.0 γ₁ [mPa s, 20° C.]: 445 PPU-TO-S 28.0 K₁ [pN,20° C.]: 16.6 CPTU-4-S 20.0 K₃ [pN, 20° C.]: 25.3 Σ 100.0 K₃/K₁ [pN, 20°C.]: 1.52 V₀ [V, 20° C.]: 1.03 LTS bulk [h, −40° C.]: 1000 τ [20° C., 19GHz]: 0.342 ε_(r,||) [20° C., 19 GHz]: 3.6922 ε_(r,⊥) [20° C., 19 GHz]:2.4308 tan δ_(ε r,||) [20° C., 19 GHz]: 0.0061 tan δ_(ε) _(r,⊥) [20° C.,19 GHz]: 0.0107 η [20° C., 19 GHz]: 32.0

Comparative Mixture C2

PPTU-4-S 6.0 T(N, I) [° C.]: 157 PPTU-5-S 12.0 Δε [1 kHz, 20° C.]: 13.5PPU-TO-S 23.0 ε_(||) [1 kHz, 20° C.]: 17.2 CPTU-5-S 25.0 ε_(⊥) [1 kHz,20° C.]: 3.7 P(2)TU-5-S 14.0 γ₁ [mPa s, 20° C.]: 604 PP(1)TU-TO-S 10.0K₁ [pN, 20° C.]: 15.4 CPU-2-S 10.0 K₃ [pN, 20° C.]: 26.0 Σ 100.0 K₃/K₁[pN, 20° C.]: 1.69 V₀ [V, 20° C.]: 1.12 LTS bulk [h, −30° C.]: 1000 τ[20° C., 19 GHz]: 0.330 ε_(r,||) [20° C., 19 GHz]: 3.6153 ε_(r,⊥) [20°C., 19 GHz]: 2.4225 tan δ_(ε r,||) [20° C., 19 GHz]: 0.0053 tan δ_(ε)_(r,⊥) [20° C., 19 GHz]: 0.0086 η [20° C., 19 GHz]: 38.4

Example N1

PTU-3-S 10.0 T(N, I) [° C.]: 156 PTU-5-S 10.0 LTS bulk [h, −30° C.]: 696PPTU-4-S 6.0 τ [20° C., 19 GHz]: 0.319 PPTU-5-S 12.0 ε_(r,||) [20° C.,19 GHz]: 3.6059 PPU-TO-S 28.0 ε_(r,⊥) [20° C., 19 GHz]: 2.4555 CPTU-4-S20.0 tan δ_(ε r,||) [20° C., 19 GHz]: 0.0057 CPU(F, F)-3-S 14.0 tanδ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0090 Σ 100.0 η [20° C., 19 GHz]: 35.4

Example N1 corresponds to Comparative Mixture C in which the compoundPGU-3-S has been replaced with the compound CPU(F,F)-3-S according tothe invention. Surprisingly this has the effect that the dielectric lossis improved (lower) which results in an improvement of the materialquality (η) from η=32.0 to 35.4.

Example N2

PPTU-4-S 6.0 T (N, I) [° C.]: 158 PPTU-5-S 12.0 Δε [1 kHz, 20° C.]: 11.9PPU-TO-S 23.0 ε_(||) [1 kHz, 20° C.]: 15.4 CPTU-5-S 25.0 ε_(⊥) [1 kHz,20° C.]: 3.5 P(2)TU-5-S 14.0 γ₁ [mPa s, 20° C.]: 647 PP(1)TU-TO-S 10.0K₁ [pN, 20° C.]: 16.7 CPU(F, F)-3-S 10.0 K₃ [pN, 20° C.]: 25.8 Σ 100.0K₃/K₁ [pN, 20° C.]: 1.55 V₀ [V, 20° C.]: 1.26 LTS bulk [h, −30° C.]:1000 τ [20° C., 19 GHz]: 0.331 ε_(r,||) [20° C., 19 GHz]: 3.6175 ε_(r,⊥)[20° C., 19 GHz]: 2.4212 tan δ_(ε) _(r,||) [20° C., 19 GHz]: 0.0050 tanδ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0080 η [20° C., 19 GHz]: 41.3

Example N2 corresponds to Comparative Mixture C in which the compoundCPU-2-S has been replaced with the compound CPU(F,F)-3-S according tothe invention. Surprisingly this has the effect that the dielectric lossis improved (lower) which results in an improvement of figure-of-meritfrom η=38.4 to 41.3.

Example N3

PGU-3-S 10.0 T (N, I) [° C.]: 158 PPTU-4-S 6.0% τ [20° C., 19 GHz]:0.321 PPTU-5-S 10.0% ε_(r,||) [20° C., 19 GHz]: 3.5700 PPU-TO-S 22.0%ε_(r,⊥) [20° C., 19 GHz]: 2.4244 CPTU-4-S 8.0% tan δ_(ε) _(r,||) [20°C., 19 GHz]: 0.0050 CPTU-5-S 12.0% tan δ_(ε) _(r,⊥) [20° C., 19 GHz]:0.0083 P(2)TU-5-S 12.0% η [20° C., 19 GHz]: 38.9 CPU(F, F)-3-S 14.0%CPU(F, F)-4-S 6.0% Σ 100.0%

Example N4

PPTU-4-S 6.0% T (N, I) [° C.]: 161.9 PPTU-5-S 12.0% LTS bulk [h, −20°C.]: 1000 PPU-TO-S 23.0% LTS bulk [h, −30° C.]: 336 CPTU-5-S 23.0% τ[20° C., 19 GHz]: 0.315 P(2)TU-5-S 12.0% ε_(r,||) [20° C., 19 GHz]:3.5604 CPU(F, F)-3-S 18.0% ε_(r,⊥) [20° C., 19 GHz]: 2.4392 CPU(F,F)-4-S 6.0% tan δ_(ε) _(r,||) [20° C., 19 GHz]: 0.0047 Σ 100.0% tanδ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0073 η [20° C., 19 GHz]: 43.2

Example N5

PPTU-4-S 6.0% T (N, I) [° C.]: 167 PPTU-5-S 10.0% Δε [1 kHz, 20° C.]:10.7 PPU-TO-S 28.0% ε_(||) [1 kHz, 20° C.]: 14.1 CPTU-4-S 20.0% ε_(⊥) [1kHz, 20° C.]: 3.3 P(2)TU-5-S 10.0% K₁ [pN, 20° C.]: 15.4 CPU(F, F)-3-S26.0% K₃ [pN, 20° C.]: 24.2 Σ 100.0% K₃/K₁ [pN, 20° C.]: 1.57 V₀ [V, 20°C.]: 1.27 LTS bulk [h, −20° C.]: 24 LTS bulk [h, −30° C.]: 48 τ [20° C.,19 GHz]: 0.320 ε_(r,||) [20° C., 19 GHz]: 3.5568 ε_(r,⊥) [20° C., 19GHz]: 2.4175 tan δ_(ε) _(r,||) [20° C., 19 GHz]: 0.0048 tan δ_(ε) _(r,⊥)[20° C., 19 GHz]: 0.0075 η [20° C., 19 GHz]: 42.7

Example N6

PPTU-4-S 6.0% T (N, I) [° C.]: 157 PPTU-5-S 12.0% Δε [1 kHz, 20° C.]:11.9 PPU-TO-S 18.0% ε_(||) [1 kHz, 20° C.]: 15.4 CPTU-5-S 24.0% ε_(⊥) [1kHz, 20° C.]: 3.5 P(2)TU-5-S 14.0% γ₁ [mPa s, 20° C.]: 657 PP(1)TU-TO-S10.0% K₁ [pN, 20° C.]: 15.5 CPU(F, F)-3-S 16.0% K₃ [pN, 20° C.]: 25.4 Σ100.0% K₃/K₁ [pN, 20° C.]: 1.65 V₀ [V, 20° C.]: 1.20 LTS bulk [h, −30°C.]: 1000 τ [20° C., 19 GHz]: 0.326 ε_(r,||) [20° C., 19 GHz]: 3.5833ε_(r,⊥) [20° C., 19 GHz]: 2.4167 tan δ_(ε) _(r,||) [20° C., 19 GHz]:0.0048 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0076 η [20° C., 19 GHz]:42.7

Example N7

PGU-3-S 6.0% T (N, I) [° C.]: 155.5 PPTU-4-S 6.0% γ₁ [mPa s, 20° C.]:613 PPTU-5-S 12.0% τ [20° C., 19 GHz]: 0.320 PPU-TO-S 20.0% ε_(r,||)[20° C., 19 GHz]: 3.5292 CPTU-5-S 22.0% ε_(r,⊥) [20° C., 19 GHz]: 2.3982P(2)TU-5-S 14.0% tan δ_(ε) _(r,||) [20° C., 19 GHz]: 0.0048 CPU(F,F)-3-S 20.0% tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0078 Σ 100.0% η [20°C., 19 GHz]: 41.0

Example N8

PPTU-4-S 6.0% T (N, I) [° C.]: 156 PPTU-5-S 12.0% τ [20° C., 19 GHz]:0.320 PPU-TO-S 20.0% ε_(r,||) [20° C., 19 GHz]: 3.5856 CPTU-5-S 22.0%ε_(r,⊥) [20° C., 19 GHz]: 2.4398 P(2)TU-5-S 14.0% tan δ_(ε) _(r,||) [20°C., 19 GHz]: 0.0049 CPU(F, F)-3-S 16.0% tan δ_(ε) _(r,⊥) [20° C., 19GHz]: 0.0077 PP(1)TU-TO-S 10.0% η [20° C., 19 GHz]: 41.6 Σ 100.0%

Example N9

CPU(F, F)-3-S  10.0% τ [20° C., 19 GHz]: 0.305 PTU-3-S 14.38% ε_(r,||)[20° C., 19 GHz]: 3.5560 PGU-3-S 12.58% ε_(r,⊥) [20° C., 19 GHz]: 2.4724PPTU-5-S 17.98% tan δ_(ε) _(r,||) [20° C., 19 GHz]: 0.0056 CPU-2-S31.46% tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0101 CPU-4-S 13.48% η [20°C., 19 GHz]: 30.2 ST-3b-1  0.12% Σ  100.0%

Example N10

PPTU-4-S 6.0% T (N, I) [° C.]: 191.5 PPTU-5-S 12.0% LTS bulk [h, −30°C.]: 24 PPU-TO-S 20.0% τ [20° C., 19 GHz]: 0.341 PGU-3-S 12.0% ε_(r,||)[20° C., 19 GHz]: 3.6334 CPTU-5-S 22.0% ε_(r,⊥) [20° C., 19 GHz]: 2.3957PP(1)TU-TO-S 12.0% tan δ_(ε) _(r,||) [20° C., 19 GHz]: 0.0048 CPU(F,F)-3-S 16.0% tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0081 Σ 100.0% η [20°C., 19 GHz]: 42.4

Example N11

PPTU-4-S 6.0% T (N, I) [° C.]: 162.5 PPTU-5-S 10.0% LTS bulk [h, −30°C.]: 24 PPU-TO-S 22.0% τ [20° C., 19 GHz]: 0.311 CPTU-4-S 12.0% ε_(r,||)[20° C., 19 GHz]: 3.5489 CPTU-5-S 18.0% ε_(r,⊥) [20° C., 19 GHz]: 2.4437P(2)TU-5-S 12.0% tan δ_(ε) _(r,||) [20° C., 19 GHz]: 0.0048 CPU(F,F)-3-S 10.0% tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0076 CPU(F, F)-4-S10.0% η [20° C., 19 GHz]: 40.9 Σ 100.0%

Example N12

PGU-3-S 10.0% T (N, I) [° C.]: 158.2 PPTU-4-S 6.0% LTS bulk [h, −30°C.]: 768 PPTU-5-S 10.0% τ [20° C., 19 GHz]: 0.319 PPU-TO-S 22.0%ε_(r,||) [20° C., 19 GHz]: 3.5820 CPTU-4-S 8.0% ε_(r,⊥) [20° C., 19GHz]: 2.4382 CPTU-5-S 12.0% tan δ_(ε) _(r,||) [20° C., 19 GHz]: 0.0051P(2)TU-5-S 12.0% tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0084 CPU(F, F)-3-S10.0% η [20° C., 19 GHz]: 38.0 CPU(F, F)-4-S 10.0% Σ 100.0%

Example N13

PTPU-4-S 6.0% PPTU-5-S 10.0% PPU-TO-S 28.0% CPTU-4-S 20.0% P(2)TU-5-S10.0% CPU(F, F)-3-S 26.0% Σ 100.0%

Example N14

PPTU-4-S  6.0% T (N, I) [° C.]: 161.9 PPTU-5-S 12.0% LTS bulk [h, −20°C.]: 1000 PPU-TO-S 23.0% LTS bulk [h, −30° C.]: 336 CPTU-5-S 23.0% τ[20° C., 19 GHz]: 0.315 P(2)TU-5-S 12.0% ε_(r,||) [20° C., 19 GHz]: 3.56CPU(F, F)-3-S 18.0% ε_(r,⊥) [20° C., 19 GHz]: 2.44 CPU(F, F)-4-S  6.0%tan δ_(ε) _(r,||) [20° C., 19 GHz]: 0.0047 Σ  100% tan δ_(ε) _(r,⊥) [20°C., 19 GHz]: 0.0073 η [20° C., 19 GHz]: 43.2

Example N15

PPTU-4-S  6.0% T (N, I) [° C.]: 158 PPTU-5-S 12.0% Δε [1 kHz, 20° C.]:11.9 PPU-TO-S 23.0% ε_(||) [1 kHz, 20° C.]: 15.4 CPTU-5-S 25.0% ε_(⊥) [1kHz, 20° C.]: 3.5 P(2)TU-5-S 14.0% γ₁ [mPa s, 20° C.]: 647 PP(1)TU-TO-S10.0% K₁ [pN, 20° C.]: 16.7 CPU(F, F)-3-S 10.0% K₃ [pN, 20° C.]: 25.8 Σ 100% K₃/K₁ [pN, 20° C.]: 1.55 V₀ [V, 20° C.]: 1.26 LTS bulk [h, −30°C.]: 1000 τ [20° C., 19 GHz]: 0.331 ε_(r,||) [20° C., 19 GHz]: 3.62ε_(r,⊥) [20° C., 19 GHz]: 2.42 tan δ_(ε) _(r,||) [20° C., 19 GHz]:0.0050 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0080 η [20° C., 19 GHz]:41.3

Example N16

PPTU-4-S  6.0% T (N, I) [° C.]: 157 PPTU-5-S 12.0% Δε [1 kHz, 20° C.]:11.9 PPU-TO-S 18.0% ε_(||) [1 kHz, 20° C.]: 15.4 CPTU-5-S 24.0% ε_(⊥) [1kHz, 20° C.]: 3.5 P(2)TU-5-S 14.0% γ₁ [mPa s, 20° C.]: 657 PP(1)TU-TO-S10.0% K₁ [pN, 20° C.]: 15.5 CPU(F, F)-3-S 16.0% K₃ [pN, 20° C.]: 25.4 Σ 100% K₃/K₁ [pN, 20° C.]: 1.65 V₀ [V, 20° C.]: 1.20 LTS bulk [h, −30°C.]: 1000 τ [20° C., 19 GHz]: 0.326 ε_(r,||) [20° C., 19 GHz]: 3.58ε_(r,⊥) [20° C., 19 GHz]: 2.42 tan δ_(ε) _(r,||) [20° C., 19 GHz]:0.0048 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0076 η [20° C., 19 GHz]:42.7

Example N17

PGU-3-S  6.0% T(N, I) [° C.]: 155.5 PPTU-4-S  6.0% Δε [1 kHz, 20° C.]:13.4 PPTU-5-S 12.0% ε_(||) [1 kHz, 20° C.]: 17.1 PPU-TO-S 20.0% ε_(⊥) [1kHz, 20° C.]: 3.7 CPTU-5-S 22.0% γ₁ [mPa s, 20° C.]: 627 P(2)TU-5-S14.0% K₁ [pN, 20° C.]: 16.0 CPU(F, F)-3-S 20.0% K₃ [pN, 20° C.]: 24.5 Σ 100% K₃/K₁ [pN, 20° C.]: 1.53 V₀ [V, 20° C.]: 1.15 LTS bulk [h, −30°C.]: 1000 LTS bulk [h, −40° C.]: 1000 τ [20° C., 19 GHz]: 0.320 ε_(r,||)[20° C., 19 GHz]; 3.53 ε_(r,⊥) [20° C., 19 GHz]: 2.40 tan δ_(ε) _(r,||)[20° C., 19 GHz]: 0.0048 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0078 η[20° C., 19 GHz]: 41.0

Example N18

PPTU-4-S  6.0% T(N, I) [° C.]: 156 PPTU-5-S 12.0% LTS bulk [h, −30° C.]:1000 PPU-TO-S 20.0% LTS bulk [h, −40° C.]: 1000 CPTU-5-S 22.0% τ [20°C., 19 GHz]: 0.320 P(2)TU-5-S 14.0% ε_(r,||) [20° C., 19 GHz]: 3.59CPU(F, F)-3-S 16.0% ε_(r,⊥) [20° C., 19 GHz]: 2.44 PP(1)TU-TO-S 10.0%tan δ_(ε) _(r,||) [20° C., 19 GHz]: 0.0049 Σ  100% tan δ_(ε) _(r,⊥) [20°C., 19 GHz]: 0.0077 η [20° C., 19 GHz]: 41.6

Example N19

PPTU-4-S 6.0 T(N, I) [° C.]: 191.5 PPTU-5-S 12.0% LTS bulk [h, −30° C.]:24 PPU-TO-S 20.0% τ [20° C., 19 GHz]: 0.341 PGU-3-S 12.0% ε_(r,||) [20°C., 19 GHz]: 3.63 CPTU-5-S 22.0% ε_(r,⊥) [20° C., 19 GHz]: 2.40PP(1)TU-TO-S 12.0% tan δ_(ε) _(r,||) [20° C., 19 GHz]: 0.0048 CPU(F,F)-3-S 16.0% tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0081 Σ  100% η [20°C., 19 GHz]: 42.4

Example N20

PPTU-4-S  6.0% T(N, I) [° C.]: 165 PPTU-5-S 14.0% Δε [1 kHz, 20° C.]:13.7 PPU-TO-S 22.0% ε_(||) [1 kHz, 20° C.]: 17.2 CPTU-5-S 22.0% ε_(⊥) [1kHz, 20° C.]: 3.5 PTU-3-S  8.0% γ₁ [mPa s, 20° C.]: 530 PTU-5-S  8.0% K₁[pN, 20° C.]: 17.6 CPU(F, F)-3-S 20.0% K₃ [pN, 20° C.]: 26.3 Σ  100%K₃/K₁ [pN, 20° C.]: 1.50 V₀ [V, 20° C.]: 1.20 LTS bulk [h, −30° C.]:1000 LTS bulk [h, −40° C.]: 552 τ [20°, 19 GHz]: 0.329 ε_(r,||) [20° C.,19 GHz]: 3.58 ε_(r,⊥) [20° C., 19 GHz]: 2.40 tan δ_(ε) _(r,||) [20° C.,19 GHz]: 0.0050 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0082 η [20° C., 19GHz]: 40.1

Example N21

PPTU-4-S  6.0% T(N, I) [° C.]: 159 PPTU-5-S 14.0% τ [20° C., 19 GHz]:0.325 PPU-TO-S 20.0% ε_(r,||) [20° C., 19 GHz]: 3.58 CPTU-5-S 18.0%ε_(r,⊥) [20° C., 19 GHz]: 2.42 PTU-3-S  8.0% tan δ_(ε) _(r,||) [20° C.,19 GHz]: 0.0049 PTU-5-S  8.0% tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0080CPU(F, F)-3-S 26.0% η [20° C., 19 GHz]: 40.6 Σ  100%

Example N22

PPTU-4-S 6.0 T(N, I) [° C.]: 156 PPTU-5-S 14.0% τ [20° C., 19 GHz]:0.316 PPU-TO-S 18.0% ε_(r,||) [20° C., 19 GHz]: 3.60 CPTU-5-S 18.0%ε_(r,⊥) [20° C., 19 GHz]: 2.46 PTU-3-S 10.0% tan δ_(ε) _(r,||) [20° C.,19 GHz]: 0.0052 PTU-5-S 10.0% tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0083CPU(F, F)-3-S 24.0% η [20° C., 19 GHz]: 38.1 Σ  100%

Example N23

PPTU-4-S  6.0% T(N, I) [° C.]: 159 PPTU-5-S 14.0% τ [20° C., 19 GHz]:0.320 PPU-TO-S 16.0% ε_(r,||) [20° C., 19 GHz]: 3.51 CPTU-5-S 18.0%ε_(r,⊥) [20° C., 19 GHz]: 2.39 PTU-3-S  9.0% tan δ_(ε) _(r,||) [20° C.,19 GHz]: 0.0049 PTU-5-S  9.0% tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0077CPU(F, F)-3-S 28.0% η [20° C., 19 GHz]: 41.6 Σ  100%

Example N24

PPTU-4-S  6.0% T(N, I) [° C.]: 165 PPTU-5-S 14.0% Δε [1 kHz, 20° C.]:14.3 PPU-TO-S 22.0% ε_(||) [1 kHz, 20° C.]: 17.9 CPTU-5-S 25.0% ε_(⊥) [1kHz, 20° C.]: 3.6 PTU-3-S  9.0% γ₁ [mPa s, 20° C.]: 522 PTU-5-S  8.0% K₁[pN, 20° C.]: 18.0 CPU(F, F)-3-S 16.0% K₃ [pN, 20° C.]: 26.0 Σ  100%K₃/K₁ [pN, 20° C.]: 1.45 V₀ [V, 20° C.]: 1.18 τ [20° C., 19 GHz]: 0.329ε_(r,||) [20° C., 19 GHz]: 3.61 ε_(r,⊥) [20° C., 19 GHz]: 2.42 tan δ_(ε)_(r,||) [20° C., 19 GHz]: 0.0051 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]:0.0084 η [20° C., 19 GHz]: 39.2

Example N25

PPTU-4-S  6.0% T(N, I) [° C.]: 165 PPTU-5-S 12.0% Δε [1 kHz, 20° C.]:13.7 PPU-TO-S 22.0% ε_(||) [1 kHz, 20° C.]: 17.2 CPTU-5-S 24.0% ε_(⊥) [1kHz, 20° C.]: 3.5 PTU-3-S  8.0% γ₁ [mPa s, 20° C.]: 535 PTU-5-S  8.0% K₁[pN, 20° C.]: 17.9 CPU(F, F)-3-S 20.0% K₃ [pN, 20° C.]: 26.1 Σ  100%K₃/K₁ [pN, 20° C.]: 1.46 V₀ [V, 20° C.]: 1.20 τ [20° C., 19 GHz]: 0.324ε_(r,||) [20° C., 19 GHz]: 3.56 ε_(r,⊥) [20° C., 19 GHz]: 2.41 tan δ_(ε)_(r,||) [20° C., 19 GHz]: 0.0051 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]:0.0081 η [20° C., 19 GHz]: 40.0

Example N26

PPTU-4-S  6.0% T(N, I) [° C.]: 164 PPTU-5-S 12.0% Δε [1 kHz, 20° C.]:14.0 PPU-TO-S 22.0% ε_(||) [1 kHz, 20° C.]: 17.5 CPTU-5-S 25.0% ε_(⊥) [1kHz, 20° C.]: 3.6 PTU-3-S  9.0% γ₁ [mPa s, 20° C.]: 529 PTU-5-S  8.0% K₁[pN, 20° C.]: 17.7 CPU(F, F)-3-S 18.0% K₃ [pN, 20° C.]: 26.2 Σ  100%K₃/K₁ [pN, 20° C.]: 1.48 V₀ [V, 20° C.]: 1.19 τ [20° C., 19 GHz]: 0.324ε_(r,||) [20° C., 19 GHz]: 3.60 ε_(r,⊥) [20° C., 19 GHz]: 2.43 tan δ_(ε)_(r,||) [20° C., 19 GHz]: 0.0051 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]:0.0083 η [20° C., 19 GHz]: 39.0

Example N27

PPTU-4-S  6.0% T(N, I) [° C.]: 162 PPTU-5-S 13.0% Δε [1 kHz, 20° C.]:14.5 PPU-TO-S 17.0% ε_(||) [1 kHz, 20° C.]: 18.1 CPTU-5-S 26.0% ε_(⊥) [1kHz, 20° C.]: 3.6 PTU-3-S  9.0% γ₁ [mPa s, 20° C.]: 522 PTU-5-S  9.0% K₁[pN, 20° C.]: 18.0 CPU(F, F)-3-S 20.0% K₃ [pN, 20° C.]: 25.3 Σ  100%K₃/K₁ [pN, 20° C.]: 1.41 V₀ [V, 20° C.]: 1.17 τ [20° C., 19 GHz]: 0.329ε_(r,||) [20° C., 19 GHz]: 3.55 ε_(r,⊥) [20° C., 19 GHz]: 2.39 tan δ_(ε)_(r,||) [20° C., 19 GHz]: 0.0049 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]:0.0080 η [20° C., 19 GHz]: 41.1

Example N28

PPTU-4-S  6.0% T(N, I) [° C.]: 157 PPTU-5-S 14.0% Δε [1 kHz, 20° C.]:14.2 PPU-TO-S 22.0% ε_(||) [1 kHz, 20° C.]: 17.8 CPTU-5-S 20.0% ε_(⊥) [1kHz, 20° C.]: 3.6 PTU-3-S 10.0% γ₁ [mPa s, 20° C.]: 486 PTU-5-S 10.0% K₁[pN, 20° C.]: 17.2 CPU(F, F)-3-S 18.0% K₃ [pN, 20° C.]: 24.6 Σ  100%K₃/K₁ [pN, 20° C.]: 1.43 V₀ [V, 20° C.]: 1.16 τ [20°, 19 GHz]: 0.325ε_(r,||) [20° C., 19 GHz]: 3.56 ε_(r,⊥) [20° C., 19 GHz]: 2.40 tan δ_(ε)_(r,||) [20° C., 19 GHz]: 0.0053 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]:0.0084 η [20° C., 19 GHz]: 38.7

Example N29

PPTU-4-S  6.0% T(N, I) [° C.]: 158 PPTU-5-S 14.0% Δε [1 kHz, 20° C.]:14.5 PPU-TO-S 20.0% ε_(||) [1 kHz, 20° C.]: 18.1 CPTU-5-S 22.0% ε_(⊥) [1kHz, 20° C.]: 3.6 PTU-3-S 10.0% γ₁ [mPa s, 20° C.]: 493 PTU-5-S 10.0% K₁[pN, 20° C.]: 17.4 CPU(F, F)-3-S 18.0% K₃ [pN, 20° C.]: 24.4 Σ  100%K₃/K₁ [pN, 20° C.]: 1.40 V₀ [V, 20° C.]: 1.16 τ [20° C., 19 GHz]: 0.324ε_(r,||) [20° C., 19 GHz]: 3.61 ε_(r,⊥) [20° C., 19 GHz]: 2.44 tan δ_(ε)_(r,||) [20° C., 19 GHz]: 0.0052 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]:0.0086 η [20° C., 19 GHz]: 37.7

Example N30

PPTU-4-S  6.0% T(N, I) [° C.]: 158 PPTU-5-S 13.0% Δε [1 kHz, 20° C.]:14.6 PPU-TO-S 20.0% ε_(||) [1 kHz, 20° C.]: 18.2 CPTU-5-S 24.0% ε_(⊥) [1kHz, 20° C.]: 3.6 PTU-3-S 10.0% γ₁ [mPa s, 20° C.]: 498 PTU-5-S 10.0% K₁[pN, 20° C.]: 17.4 CPU(F, F)-3-S 17.0% K₃ [pN, 20° C.]: 24.6 Σ  100%K₃/K₁ [pN, 20° C.]: 1.41 V₀ [V, 20° C.]: 1.15 LTS bulk [h, −30° C.]: 168LTS bulk [h, −40° C.]: 1000 τ [20° C., 19 GHz]: 0.328 ε_(r,||) [20° C.,19 GHz]: 3.61 ε_(r,⊥) [20° C., 19 GHz]: 2.43 tan δ_(ε) _(r,||) [20° C.,19 GHz]: 0.0052 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0085 η [20° C., 19GHz]: 38.6

Example N31

PPTU-4-S  6.0% T(N, I) [° C.]: 159 PPTU-5-S 14.0% Δε [1 kHz, 20° C.]:14.9 PPU-TO-S 17.0% ε_(||) [1 kHz, 20° C.]: 18.5 CPTU-5-S 25.0% ε_(⊥) [1kHz, 20° C.]: 3.6 PTU-3-S 10.0% γ₁ [mPa s, 20° C.]: 497 PTU-5-S 10.0% K₁[pN, 20° C.]: 17.3 CPU(F, F)-3-S 18.0% K₃ [pN, 20° C.]: 25.0 Σ  100%K₃/K₁ [pN, 20° C.]: 1.45 V₀ [V, 20° C.]: 1.15 τ [20° C., 19 GHz]: 0.327ε_(r,||) [20° C., 19 GHz]: 3.57 ε_(r,⊥) [20° C., 19 GHz]: 2.40 tan δ_(ε)_(r,||) [20° C., 19 GHz]: 0.0051 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]:0.0083 η [20° C., 19 GHz]: 39.4

Example N32

PPTU-4-S  6.0% T(N, I) [° C.]: 159 PPTU-5-S 14.0% Δε [1 kHz, 20° C.]:14.9 PPU-TO-S 16.0% ε_(∥) [1 kHz, 20° C.]: 18.5 CPTU-5-S 25.0% ε_(⊥) [1kHz, 20° C.]: 3.6 PTU-3-S 10.0% γ₁ [mPa s, 20° C.]: 503 PTU-5-S 10.0% K₁[pN, 20° C.]: 17.6 CPU(F, F)-3-S 19.0% K₃ [pN, 20° C.]: 25.0 Σ  100%K₃/K₁ [pN, 20° C.]: 1.42 V₀ [V, 20° C.]: 1.15 τ [20° C., 19 GHz]: 0.326ε_(r,∥) [20° C., 19 GHz]: 3.58 ε_(r,⊥) [20° C., 19 GHz]: 2.41 tan δ_(ε)_(r,∥) [20° C., 19 GHz]: 0.0050 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]:0.0083 η [20° C., 19 GHz]: 39.3

Example N34

PPTU-4-S  6.0% T(N, I) [° C.]: 159 PPTU-5-S 15.0% Δε [1 kHz, 20° C.]:15.1 PPU-TO-S 16.0% ε_(∥) [1 kHz, 20° C.]: 18.7 CPTU-5-S 25.0% ε_(⊥) [1kHz, 20° C.]: 3.6 PTU-3-S 10.0% γ₁ [mPa s, 20° C.]: 505 PTU-5-S 10.0% K₁[pN, 20° C.]: 17.7 CPU(F, F)-3-S 18.0% K₃ [pN, 20° C.]: 24.7 Σ  100%K₃/K₁ [pN, 20° C.]: 1.39 V₀ [V, 20° C.]: 1.14 LTS bulk [h, −40° C.]: 936τ [20° C., 19 GHz]: 0.326 ε_(r,∥) [20° C., 19 GHz]: 3.57 ε_(r,⊥) [20°C., 19 GHz]: 2.40 tan δ_(ε) _(r,∥) [20° C., 19 GHz]: 0.0050 tan δ_(ε)_(r,⊥) [20° C., 19 GHz]: 0.0083 η [20° C., 19 GHz]: 39.3

Example N35

PPTU-4-S  6.0% T(N, I) [° C.]: 159 PPTU-5-S 14.0% Δε [1 kHz, 20° C.]:15.0 PPU-TO-S 16.0% ε_(∥) [1 kHz, 20° C.]: 18.6 CPTU-5-S 26.0% ε_(⊥) [1kHz, 20° C.]: 3.6 PTU-3-S 10.0% γ₁ [mPa s, 20° C.]: 503 PTU-5-S 10.0% K₁[pN, 20° C.]: 17.6 CPU(F, F)-3-S 18.0% K₃ [pN, 20° C.]: 24.6 Σ  100%K₃/K₁ [pN, 20° C.]: 1.40 V₀ [V, 20° C.]: 1.14 τ [20° C., 19 GHz]: 0.320ε_(r,∥) [20° C., 19 GHz]: 3.60 ε_(r,⊥) [20° C., 19 GHz]: 2.45 tan δ_(ε)_(r,∥) [20° C., 19 GHz]: 0.0051 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]:0.0084 η [20° C., 19 GHz]: 38.1

Example N36

PPTU-4-S  6.0% T(N, I) [° C.]: 158 PPTU-5-S 15.0% Δε [1 kHz, 20° C.]:15.5 PPU-TO-S 13.0% ε_(∥) [1 kHz, 20° C.]: 19.1 CPTU-5-S 27.0% ε_(⊥) [1kHz, 20° C.]: 3.7 PTU-3-S 10.0% γ₁ [mPa s, 20° C.]: 491 PTU-5-S 11.0% K₁[pN, 20° C.]: 17.7 CPU(F, F)-3-S 18.0% K₃ [pN, 20° C.]: 24.4 Σ  100%K₃/K₁ [pN, 20° C.]: 1.38 V₀ [V, 20° C.]: 1.13 τ [20° C., 19 GHz]: 0.326ε_(r,∥) [20° C., 19 GHz]: 3.58 ε_(r,⊥) [20° C., 19 GHz]: 2.42 tan δ_(ε)_(r,∥) [20° C., 19 GHz]: 0.0050 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]:0.0083 η [20° C., 19 GHz]: 39.3

Example N37

PPTU-4-S  6.0% T(N, I) [° C.]: 159 PPTU-5-S 16.0% Δε [1 kHz, 20° C.]:15.9 PPU-TO-S 11.0% ε_(∥) [1 kHz, 20° C.]: 19.5 CPTU-5-S 28.0% ε_(⊥) [1kHz, 20° C.]: 3.7 PTU-3-S 10.0% γ₁ [mPa s, 20° C.]: 494 PTU-5-S 11.0% K₁[pN, 20° C.]: 18.1 CPU(F, F)-3-S 18.0% K₃ [pN, 20° C.]: 24.6 Σ  100%K₃/K₁ [pN, 20° C.]: 1.36 V₀ [V, 20° C.]: 1.13 τ [20° C., 19 GHz]: 0.320ε_(r,∥) [20° C., 19 GHz]: 3.55 ε_(r,⊥) [20° C., 19 GHz]: 2.41 tan δ_(ε)_(r,∥) [20° C., 19 GHz]: 0.0049 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]:0.0081 η [20° C., 19 GHz]: 39.5

Example N38

PTU-3-S 10.0% T(N, I) [° C.]: 157 PTU-5-S 10.0% τ [20° C., 19 GHz]:0.331 PPTU-4-S  6.0% ε_(r,∥) [20° C., 19 GHz]: 3.58 PPTU-5-S 12.0%ε_(r,⊥) [20° C., 19 GHz]: 2.40 PGTU-4-S  6.0% tan δ_(ε) _(r,∥) [20° C.,19 GHz]: 0.0050 PGU-3-S 16.0% tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0094CPU(F, F)-3-S 15.0% η [20° C., 19 GHz]: 35.2 CPTU-5-S 25.0% Σ  100%

Example N39

PPTU-4-S 10.0% T(N, I) [° C.]: 170.5 PPTU-5-S 20.0% Δε [1 kHz, 20° C.]:15.4 CPTU-5-S 30.0% ε_(∥) [1 kHz, 20° C.]: 18.7 PTU-5-S 15.0% ε_(⊥) [1kHz, 20° C.]: 3.4 CPU(F, F)-3-S 25.0% K₁ [pN, 20° C.]: 19.2 Σ  100% K₃[pN, 20° C.]: 23.8 K₃/K₁ [pN, 20° C.]: 1.24 V₀ [V, 20° C.]: 1.18 τ [20°C., 19 GHz]: 0.325 ε_(r,∥) [20° C., 19 GHz]: 3.55 ε_(r,⊥) [20° C., 19GHz]: 2.40 tan δ_(ε) _(r,∥) [20° C., 19 GHz]: 0.0042 tan δ_(ε) _(r,⊥)[20° C., 19 GHz]: 0.0070 η [20° C., 19 GHz]: 46.8

Example N40

PTU-3-S 10.0% T(N, I) [° C.]: 157 PTU-5-S 10.0% τ [20° C., 19 GHz]:0.328 PPTU-4-S  6.0% ε_(r,∥) [20° C., 19 GHz]: 3.67 PPTU-5-S 12.0%ε_(r,⊥) [20° C., 19 GHz]: 2.47 PGU-3-S 10.0% tan δ_(ε) _(r,∥) [20° C.,19 GHz]: 0.0056 PPU-TO-S 20.0% tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0099CPTU-5-S 22.0% η [20° C., 19 GHz]: 33.1 CPU(F, F)-3-S 10.0% Σ  100%

Example N41

PTU-3-S 10.0% T(N, I) [° C.]: 158.5 PTU-5-S 10.0% τ [20° C., 19 GHz]:0.326 PPTU-4-S  6.0% ε_(r,∥) [20° C., 19 GHz]: 3.63 PPTU-5-S 13.0%ε_(r,⊥) [20° C., 19 GHz]: 2.45 PGU-3-S  5.0% tan δ_(ε) _(r,∥) [20° C.,19 GHz]: 0.0055 PPU-TO-S 18.0% tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0092CPTU-5-S 25.0% η [20° C., 19 GHz]: 35.7 CPU(F, F)-3-S 13.0% Σ  100%

Example N42

PTU-3-S 10.0% T(N, I) [° C.]: 157.5 PTU-5-S 10.0% τ [20° C., 19 GHz]:0.331 PPTU-4-S  6.0% ε_(r,∥) [20° C., 19 GHz]: 3.67 PPTU-5-S 12.0%ε_(r,⊥) [20° C., 19 GHz]: 2.46 PGU-3-S 12.0% tan δ_(ε) _(r,∥) [20° C.,19 GHz]: 0.0058 PPU-TO-S 20.0% tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0102CPTU-5-S 24.0% η [20° C., 19 GHz]: 32.4 CPU(F, F)-3-S  6.0% Σ  100%

Example N43

ST-3b-1 0.12 T(N, I) [° C.]: 158 PPTU-4-S 5.9928 Δn [589 nm, 20° C.]:0.4015 PPU-5-S 14.982 n_(e) [589 nm, 20° C.]: 1.9286 PPU-TO-S 15.9808n_(o) [589 nm, 20° C.]: 1.5271 CPTU-5-S 24.97 Δε [1 kHz, 20° C.]: 15.0PTU-3-S 9.988 ε_(∥) [1 kHz, 20° C.]: 18.6 PTU-5-S 9.988 ε_(⊥) [1 kHz,20° C.]: 3.6 CPU(F, F)-3-S 17.9784 γ₁ [mPa s, 20° C.]: 492 Σ 93.0% 0 K₁[pN, 20° C.]: 17.6 K₃ [pN, 20° C.]: 24.4 K₃/K₁ [pN, 20° C.]: 1.39 V₀ [V,20° C.]: 1.14 LTS bulk [h, −30° C.]: 1000 LTS bulk [h, −40° C.]: 960 τ[20° C., 19 GHz]: 0.328 ε_(r,∥) [20° C., 19 GHz]: 3.59 ε_(r,⊥) [20° C.,19 GHz]: 2.42 tan δ_(ε) _(r,∥) [20° C., 19 GHz]: 0.0052 tan δ_(ε) _(r,⊥)[20° C., 19 GHz]: 0.0084 η [20° C., 19 GHz]: 39.0

Example N44

ST-3b-1 0.12 T(N, I) [° C.]: 157.5 PPTU-4-S 5.9928 Δε [1 kHz, 20° C.]:14.5 PPU-5-S 12.9844 ε_(∥) [1 kHz, 20° C.]: 18.2 PPU-TO-S 19.976 ε_(⊥)[1 kHz, 20° C.]: 3.6 CPTU-5-S 23.9712 γ₁ [mPa s, 20° C.]: 491 PTU-3-S9.988 K₁ [pN, 20° C.]: 17.3 PTU-5-S 9.988 K₃ [pN, 20° C.]: 25.0 CPU(F,F)-3-S 16.9796 K₃/K₁ [pN, 20° C.]: 1.44 Σ 93.0% 0 V₀ [V, 20° C.]: 1.16LTS bulk [h, −30° C.]: 720 LTS bulk [h, −40° C.]: 1000 τ [20° C., 19GHz]: 0.327 ε_(r,∥) [20° C., 19 GHz]: 3.59 ε_(r,⊥) [20° C., 19 GHz]:2.42 tan δ_(ε) _(r,∥) [20° C., 19 GHz]: 0.0053 tan δ_(ε) _(r,⊥) [20° C.,19 GHz]: 0.0086 η [20° C., 19 GHz]: 38.0

Example N45

PTU-3-S 10.0% T(N, I) [° C.]: 157 PTU-5-S 10.0% Δε [1 kHz, 20° C.]: 19.2PPTU-4-S  6.0% ε_(∥) [1 kHz, 20° C.]: 23.1 PPTU-5-S 15.0% ε_(⊥) [1 kHz,20° C.]: 3.9 PGU-3-S 15.0% γ₁ [mPa s, 20° C.]: 482 PPU-TO-S  7.0% K₁[pN, 20° C.]: 18.9 CPTU-5-S 24.0% K₃ [pN, 20° C.]: 24.4 CPU(F, F)-3-S13.0% K₃/K₁ [pN, 20° C.]: 1.29 Σ  100% V₀ [V, 20° C.]: 1.05 τ [20° C.,19 GHz]: 0.328 ε_(r,∥) [20° C., 19 GHz]: 3.59 ε_(r,⊥) [20° C., 19 GHz]:2.41 tan δ_(ε) _(r,∥) [20° C., 19 GHz]: 0.0053 tan δ_(ε) _(r,⊥) [20° C.,19 GHz]: 0.0094 η [20° C., 19 GHz]: 34.8

Example N46

PTU-3-S 10.0% T(N, I) [° C.]: 159 PTU-5-S  6.0% Δε [1 kHz, 20° C.]: 19.7PPTU-4-S  6.0% ε_(∥) [1 kHz, 20° C.]: 23.7 PPTU-5-S 12.0% ε_(⊥) [1 kHz,20° C.]: 4.0 PGTU-4-S  6.0% γ₁ [mPa s, 20° C.]: 596 PGU-3-S 10.0% K₁[pN, 20° C.]: 19.6 CPTU-5-S 10.0% K₃ [pN, 20° C.]: 20.9 PPU-TO-S 10.0%K₃/K₁ [pN, 20° C.]: 1.06 CPU(F, F)-3-S 10.0% V₀ [V, 20° C.]: 1.05PPTU-4(1^([2]))-S 20.0% τ [20° C., 19 GHz]: 0.339 Σ  100% ε_(r,∥) [20°C., 19 GHz]: 3.70 ε_(r,⊥) [20° C., 19 GHz]: 2.45 tan δ_(ε) _(r,∥) [20°C., 19 GHz]: 0.0050 tan δ_(ε) _(r,⊥) [20° C., 19 GHz]: 0.0090 η [20° C.,19 GHz]: 37.8

Example N46

PTU-3-S 10.0% T(N, I) [° C.]: 154 PTU-5-S 10.0% PPTU-4-S  6.0% PPTU-5-S15.0% PGU-3-S 15.0% PPU-TO-S  7.0% CPTU-5-S 24.0% CPU(F, F)-3-S 13.0% Σ 100%

The liquid-crystalline media according to the invention exhibit highclearing temperatures in combination with very good LTS and excellentmicrowave-application relevant properties. Compared to the media knownfrom the state of the art, higher material quality (η) is observed dueto higher tunability (τ) and/or lower dielectric loss (tan δ).

The invention claimed is:
 1. A compound of formula U

in which R^(U) denotes H, alkyl or alkoxy having 1 to 12 C atoms, oralkenyl, alkenyloxy or alkoxyalkyl having 2 to 12 C atoms, in which oneor more CH₂ groups may be replaced by

 or a group R^(P), R^(P) denotes halogen, CN, NCS, R^(F), R^(F)—O— orR^(F)—S—, wherein R^(F) denotes fluorinated alkyl having 1 to 9 C atomsor fluorinated alkenyl having 2 to 9 C atoms, Z^(U1), Z^(U2) identicallyor differently, denote —CH═CH—, —CH═CF—, —CH═CF—, —CF═CH—, —C≡C— or asingle bond, X¹, X², X³ and X⁴ identically or differently, denote Cl orF, t is 0 or 1, and

 identically or differently, denote a radical selected from: the groupconsisting of 1,4-phenylene, 1,4-naphthylene, and 2,6-naphthylene, inwhich one or two CH groups may be replaced by N and in which one or moreH atoms may be replaced by L, wherein tetrafluoro-1,4-phenylene isexcluded, b) the group consisting of trans-1,4-cyclohexylene,1,4-cyclo-hexenylene, bicyclo[1.1.1]pentane-1,3-diyl,4,4′-bicyclohexylene, bicyclo[2.2.2]octane-1,4-diyl, andspiro[3.3]heptane-2,6-diyl, in which one or more non-adjacent CH₂ groupsmay be replaced by —O— and/or —S— and in which one or more H atoms maybe replaced by F, c) the group consisting of thiophene-2,5-diyl,thieno[3,2-b]thiophene-2,5-diyl, and selenophene-2,5-diyl, each of whichmay also be mono- or polysubstituted by L, L on each occurrence,identically or differently, denotes F, Cl, CN, SCN, SF₅ orstraight-chain, in each case optionally fluorinated, alkyl, alkoxy,alkylcarbonyl, alkoxy-carbonyl, alkylcarbonyloxy or alkoxycarbonyloxyhaving 1 to 12 C atoms or branched, in each case optionally fluorinated,alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy oralkoxycarbonyloxy having 3 to 12 C atoms.
 2. The compound according toclaim 1, wherein

 on each occurrence, independently of one another, denote

 wherein  alternatively denotes

 and L¹ and L² identically or differently, denote F, Cl or a straightchain alkyl having 1 to 12 C atoms or branched or cyclic alkyl having 3to 12 C atoms or straight chain alkenyl each having 2 to 12 C atoms orbranched or cyclic alkenyl having 3 to 12 C atoms.
 3. The compoundaccording to claim 1, wherein Z^(U1) and Z^(U2), identically ordifferently, denote —C≡C— or a single bond.
 4. The compound according toclaim 1, wherein the compound is selected from the group consisting ofcompounds of formulae U-1 to U-11

in which L¹, L² and L³ identically or differently, denote H, F, Cl,methyl, ethyl, n-propyl, isopropyl, cyclopropyl, cyclobutyl, cyclopentylor cyclopentenyl, and R^(U), X¹, X², X³ and X⁴ have the meanings givenfor formula U.
 5. The compound according to claim 1, wherein X¹, X², X³and X⁴ denote F.
 6. The compound according to claim 1, wherein R^(U)denotes alkyl having 1 to 12 C atoms.
 7. The compound according to claim1, wherein R^(U) denotes R^(P) as defined for formula U.
 8. A liquidcrystal medium comprising one or more compounds according to claim
 1. 9.The liquid crystal medium according to claim 8, wherein the mediumfurther comprises one or more compounds selected from the groupconsisting of compounds of formulae I, II and III,

in which R¹ denotes H, unfluorinated alkyl or unfluorinated alkoxyhaving 1 to 17 C atoms, or unfluorinated alkenyl, unfluorinatedalkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 C atoms, in whichone or more CH₂-groups may be replaced by

n is 0, 1 or 2,

 to

on each occurrence, independently of one another, denote

in which R^(L), on each occurrence identically or differently, denotes Hor alkyl having 1 to 6 C atoms, and wherein

 alternatively denotes

R² denotes H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17C atoms, or unfluorinated alkenyl, unfluorinated alkenyloxy orunfluorinated alkoxyalkyl having 2 to 15 C atoms, in which one or moreCH₂-groups may be replaced by

Z²¹ denotes trans-CH═CH—, trans-CF═CF— or —C≡C—, and

independently of one another, denote

in which R^(L), on each occurrence identically or differently, denotes Hor alkyl having 1 to 6 C atoms; R³ denotes H, unfluorinated alkyl orunfluorinated alkoxy having 1 to 17 C atoms, or unfluorinated alkenyl,unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 Catoms, in which one or more CH₂-groups may be replaced by

one of Z³¹ and Z³² denotes trans-CH═CH—, trans-CF═CF— or —C≡C— and theother one, independently thereof, denotes —C≡C—, trans-CH═CH—,trans-CF═CF— or a single bond, and

 to

independently of one another, denote

in which R^(L), on each occurrence identically or differently, denotes Hor alkyl having 1 to 6 C atoms, and wherein

 alternatively denotes


10. The liquid crystal medium according to claim 9, wherein the mediumcomprises one or more compounds selected from the group consisting ofcompounds of formulae I-1 to I-5

in which L¹, L² and L³ on each occurrence, identically or differently,denote H or F, and R¹,

 have the meanings given for formula I.
 11. The liquid crystal mediumaccording to claim 9, wherein the medium comprises one or more compoundsselected from the group consisting of compounds of formulae II-1 to II-3

in which R²,

 have the meanings given for formula II.
 12. The liquid crystal mediumaccording to claim 9, wherein the medium comprises one or more compoundsselected from the group consisting of compounds of formulae III-1 toIII-6

in which R³,

 have the meanings given for formula III, and Z³¹ and Z³² independentlyof one another, denote trans-CH═CH— or trans-CF═CF—, and in formulaIII-6 alternatively one of Z³¹ and Z³² may denote —C≡C—.
 13. A componentfor high-frequency technology, comprising the liquid crystal mediumaccording to claim
 8. 14. The component according to claim 13, which isa liquid-crystal based antenna element, a phase shifter, a tunablefilter, a tunable metamaterial structure, a matching network or avaractor.
 15. A microwave antenna array, comprising one or morecomponents according to claim
 13. 16. A compound selected from the groupconsisting of compounds 1 to 50 11,2,4,5-Tetrafluoro-3-isothiocyanato-6-[4-(4-propylcyclohexyl)phenyl]benzene 21,2,4,5-Tetrafluoro-3-isothiocyanato-6-[4-[4-(trifluoromethoxy)phenyl]phenyl]benzene 31-[4-[2-(4-Butylphenyl)ethynyl]phenyl]-2,3,5,6-tetrafluoro-4-isothiocyanato-benzene 41,2,4,5-Tetrafluoro-3-isothiocyanato-6-[4-[2-[4-(trifluoromethoxy)phenyl]ethynyl]phenyl]benzene 5

6

7

8

9

10

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12

13

14

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16

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19

20

21

22

23

24

25

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51

52


17. A liquid crystal medium comprising one or more compounds accordingto claim
 16. 18. The liquid crystal medium according to claim 17,wherein the medium further comprises one or more compounds selected fromthe group consisting of compounds of formulae I, II and III,

in which R¹ denotes H, unfluorinated alkyl or unfluorinated alkoxyhaving 1 to 17 C atoms, or unfluorinated alkenyl, unfluorinatedalkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 C atoms, in whichone or more CH₂-groups may be replaced by

n is 0, 1 or 2,

on each occurrence, independently of one another, denote

in which R^(L), on each occurrence identically or differently, denotes Hor alkyl having 1 to 6 C atoms, and wherein

 alternatively denotes

R² denotes H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17C atoms, or unfluorinated alkenyl, unfluorinated alkenyloxy orunfluorinated alkoxyalkyl having 2 to 15 C atoms, in which one or moreCH₂-groups may be replaced by

Z²¹ denotes trans-CH═CH—, trans-CF═CF— or —C≡C—, and

independently of one another, denote

in which R^(L), on each occurrence identically or differently, denotes Hor alkyl having 1 to 6 C atoms; R³ denotes H, unfluorinated alkyl orunfluorinated alkoxy having 1 to 17 C atoms, or unfluorinated alkenyl,unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 Catoms, in which one or more CH₂-groups may be replaced by

one of Z³¹ and Z³² denotes trans-CH═CH—, trans-CF═CF— or —C≡C— and theother one, independently thereof, denotes —C≡C—, trans-CH═CH—,trans-CF═CF— or a single bond, and

independently of one another, denote

in which R^(L), on each occurrence identically or differently, denotes Hor alkyl having 1 to 6 C atoms, and wherein

 alternatively denotes


19. A component for high-frequency technology, comprising the liquidcrystal medium according to claim
 17. 20. The component according toclaim 19, which is a liquid-crystal based antenna element, a phaseshifter, a tunable filter, a tunable metamaterial structure, a matchingnetwork, a varactor, or a microwave antenna array.